AITA for blowing up and exposing my girlfriend to her family

I(25m) have been with my girlfriend(24f) for about five years now before we got together she had a baby from her past relationship and he was about two months old when we met. I knew that I would have to step up and accept him if I wanted to have her and that was never a problem to me. From that day on when we made it official, I accepted him as my son and never treated him as anything different. It was also never an issue with me to do that because she assured me that the biological father would not be involved considering he hasn’t been present since she was about two months pregnant. About five months into our relationship she got a text from a random number and it was him. He was saying awful dirty mean things to her and me being her boyfriend I had to step up and defend her and he said awful things to me as well that will go on maybe once every year and a half and he had been about three years since we had heard from him the last time that was until early December 2025. He texted her saying he was a change person and would like to be present in our son‘s life. I didn’t find out until Christmas Eve on our way home from a Christmas party. She had drank up enough courage to tell me which was strange because every other time he texted her, she would tell me right away. She asked me if I was OK with him being in his and at first I said no obviously because I’ve been his dad for his whole entire life pretty much but she convinced me I was being selfish and I needed to think about our son so I said that’s fine. It would take some getting used to January 9 rolls around and she tells me that one of her best friends wants her to come out to the bar and hang out which was normal and I usually didn’t really care so of course I said yes she goes out for about five hours in returns home around 2:30 AM which was normal because her and her friend would stay until last call so I didn’t think twice about it about she called me about 12 times back to back to back on her way home and woke me up asking me if I was angry at her but I had been asleep the whole time. Usually she doesn’t even wake me up she’ll just lay down and go to bed or sleep on the couch if me and our children took up the whole bed. She tells me she ended up, just picking up her two friends from the bar and dropping one of them off and her and her best friend sitting in the car for a few hours hanging out because she didn’t like the other girl and that her best friend was staying the night with the other girl so they just hung out in the car which sounds like something she would do so I didn’t think twice of it. 10 days later she tells me she wants to go out again with the same friend at the same bar so of course I said yes I’ve never been the guy to say no or care but she ended up having too much to drink at a family member’s house and ended up staying home that night. I have been curious for a while what they talked about and how often they talked because she never really brought it up to me after she told me on Christmas Eve. So I went through her phone that night to see what they were talking about. I checked her iMessage and there were no messages. I even looked on the recently deleted, and there were no messages I went directly to Snapchat. I didn’t see anyone out of the ordinary on her Snapchat feed so I checked her best friends and sure enough he was at the top. I think clicked his name to see if they had talked and I see a message from her saying “ are you awake? I’m coming tonight.” I instantly called one of my best friends and told him the situation because I didn’t know what else to do. She didn’t end up going. I’m assuming because she had some sort of conscience. that’s what I like to believe at least. I also checked the Day Day. They became friends on Snapchat and it happened to be the night “ she went to the bar with her friend”. The next Friday after that night, I was at the grocery store by myself and she texted me.” do you care if I go hang out at the bar with my friend tonight?” I instantly knew who she was going to go see when I got home from the grocery store. I put the groceries away and she was laying in bed with our kids putting them to sleep. I said yes I didn’t mind because I just wanted to see if she would do it in my face again. The same anxious feeling she had the very first night she expressed to me again. I also didn’t mention earlier that she would turn off her location so that her mother didn’t see where she went because her mother was very against her going out to the bar and that she should stay home and be with me and my kids so when she first told me she would do that I didn’t mind because her mom was very very critical and hard on her and I knew how upset it made her when her mother would get on her so I didn’t oblige. She goes out to her car to start it and warm it up and fill up her tire because it was low on air. she comes in being all touchy fairly towards me, trying to put her cold hands up my shirt and make me laugh and tickle, and all that mind you since he came into the picture we had only been intimate one time and it did not feel right for a single second I said to her “ you haven’t let me touch you and you haven’t touched me in almost 2 months so why are you acting like this?” this part really stings she kisses me on the lips and tells me that she loves me on her way out the door to go see her ex-boyfriend. I didn’t know what else to do so I took a couple melatonin so I could go to sleep fast so I can get my mind off of it and by the time I’m done in the kitchen, taking my melatonin and getting a drink, I look at our bedroom window to see her still sitting in the car and I texted her saying “ why haven’t you left yet?” And she responded “ I’m not sure if I want to go. It’s very cold and I am just nervous about driving tonight”. She eventually comes in. We sit down and talk for a minute and we go lay down as we’re laying down. She gets three calls back to back to back and every single time her phone would ring. She would instantly decline the call and shove the pill the phone under her pillow. I asked her who was calling her and she said it was just her friend calling off of her boyfriend‘s phone and that’s why the number was unsaved, but before she left, she told me her and her friend were broken up. That’s why her friend has been going to the bar so much so right there I knew something wasn’t right and I ended up not being able to go to sleep I stayed up all night tossing and turning dozing off for about 10 minutes and waking back up for about 10 minutes that went on for about four or five hours until I woke up and couldn’t go back to sleep so I took her phone and looked through it to see if I was right and she had it on airplane mode as soon as I took it off airplane mode the text messages came flowing from him. He was talking about how she was a liar how it was cute in the beginning but now it’s over saying that she can just forget about him and continue to be with me and be miserable. And it turns out she didn’t come back inside because she was unsure about going. It turns out she came back inside because she thought he fell asleep because he wasn’t responding so I instantly wake her up and tell her, I know where she was going, and I knew about the time before that, but I didn’t want to accuse her unless I had evidence. She just laid their silently covering her face up, saying she was embarrassed and couldn’t look at me. She said all that before she even apologized, she wouldn’t speak to me. Wouldn’t look at me just laid their silently quietly crying. We ended up falling back asleep and I went to work the next morning. I texted her taking partial responsibility because usually when someone cheats it it’s because they’re not getting something at home and I took responsibility because I may have been lacking in some areas and I would’ve much rather known that instead of it going down the way it did. We ended up talking it out and we’re fine after that and agreed that they only talk on iMessage and that messages get deleted a couple of weeks later. We had a few drinks at her sister‘s house and I’m still not secure in our relationship at this point, and I was standing behind her while she was texting someone and I was looking at her phone and she turned around and told me you were acting just like he used to act do you realize that and that sent me off. I told her in the beginning of our relationship that I don’t like being compared to other guys especially not her ex. It’s really all a blur, but I ended up telling her brother-in-law, her sister and one of her friends about everything that had happened between us and they had no idea that she had planned to meet up with her ex-boyfriend on multiple occasions my episode lasted about 20 minutes and after I just felt terrible. The next day I stayed home from work and wanted to talk to her about it I apologize for going off and acting the way I did and all she cared about was that I ruined her image towards her friend and family not that she hurt me or that she even cared that she hurt me that she was worried about what her family and her friends would think of her she would make me feel crazy every time I felt insecure before all of this and would tell me that I just needed to get over it. I didn’t want to talk to anybody about it because I didn’t want anyone to see her in a different light but you see what happens when you hold it in it never ends right I almost lost my relationship and I still decided to stay with her after her pretty much shifting the whole entire blame on me and making me feel crazy. Was I wrong for that?