Should I break up or wait for things to get better?

Hey, first of all, I’m not really sure if this is the right place to talk about this, but I feel like I’m going crazy and I really need some advice.
For some context, I’ve been with my boyfriend for 6 months, and we’ve been in a long-distance relationship (LDR) for a little less than a month. I usually go back to my parents’ place every summer for about two months, and I spend the rest of the year studying in the same city as him.
We got together pretty quickly. We met at a bar, I found his Instagram through some mutual friends, he invited me out to dinner, and we kissed when he walked me home. The following weekend, he came to sleep at my place, and we’ve basically been living together ever since.
A few days before I went back to my parents’ place, I went through his phone (I know that’s not very healthy), and I found some messages that really messed me up.
There was a message to his best friend from the day I reached out to him again after we met at the bar, where he said, and I quote, “She’s not very pretty, but she has big boobs.”
There were also other updates he sent to his friends about us at the beginning of our relationship, when he was sleeping at my place every night. He said that he didn’t want anything serious and was just waiting for me to let him get his dick wet — something he never told me. As far as I was concerned, our relationship was supposed to be serious from the beginning.
There were also some really weird situations, like when he invited me to parties with his friends and a girl he had a history with that I didn’t know about. It felt like he was using me as some kind of funny story, like, “Haha, look, I brought my girlfriend and the girl I wanted. Let’s see how this goes.”
All of this hurt me so much. It was a huge blow to my pride and my self-confidence.
If he thought I was “not very pretty,” then why would he date me and kiss me? On top of that, he was the one who asked me to be his girlfriend. I just don’t understand.
We talked about it, and I cried a lot. He apologized for hurting me and told me that he doesn’t feel that way anymore.
The problem is that I can’t stop thinking about it. It’s eating me alive. I feel hideous, and I can’t even look at myself in the mirror anymore. I also struggle with bulimia, and this has made my binge episodes and my body dysmorphia much worse.
But I don’t talk to him about it because I don’t want to be a burden.
The problem now is that, since we’ve been in an LDR, I can’t bring myself to put any effort into the relationship. I haven’t replied to his messages since yesterday. The smallest thing he does irritates me.
What I found out had already made me feel differently about him, even when we were living together, but now it feels even worse.
On top of that, he does things that I find disrespectful.
He had a female friend who was going through a difficult time, so he cut his vacation short to go stay with her. He went to her city and slept at her place. I found that disrespectful, but I didn’t say anything because I kept telling myself that she needed support.
Yesterday, he was telling his friend in a group chat that this girl was going to come out with them this weekend. She lives in another city, and I highly doubt she would go home late at night, especially if they’re going to be drinking. So she’ll probably end up sleeping at his place because she doesn’t know anyone else there.
He hasn’t said anything to me about it.
I don’t know in what world it’s considered normal to sleep at the same place as another girl while your girlfriend is away.
I can’t take this anymore. I didn’t sleep at all last night, and all of this is making me incredibly anxious.
Despite everything, I love him so much, and I don’t necessarily want to break up with him.
I know you might be wondering why I don’t just talk to him about it, but simply put, I have borderline personality disorder, and I’m trying to avoid anything that could trigger an episode. Especially because, early on in our relationship, he used to talk about how much he hated his relationship with his ex, whom he described as “depressive,” and how much he hated the fact that they argued all the time.
So I’m terrified that he’ll see me as being like her and think that I’m starting drama or being “depressive.”
I’d rather keep my pain to myself because my ex left me at a time when I was struggling very badly mentally and had to be hospitalized in a psychiatric unit. He used to say that I was “too much to handle,” and that experience traumatized me. So I’m terrified that the same thing will happen again.
But I just can’t take it anymore. I keep everything inside so much that I feel like I’m going to explode.
I can’t talk to him anymore. I can’t communicate with him. I shut down and stop talking to him, which makes things even more complicated since we’re in a long-distance relationship.
I don’t know what to do.
I don’t know if I should end the relationship. I don’t know if things will get better. I don’t know if things will ever go back to the way they were. I don’t know if I’ll ever be able to move past this.
I don’t know if I’m valid for feeling this way.
I don’t see him the same way anymore.
I don’t know what to do.
Should I just break up with him?