AITA for being upset that my mom and my boyfriend’s dad are dating?

I need some advice. To preface me and my mom have never have a good relationship and I just started living with her again back in january after being kicked out by her and not living with her for 8 months. My boyfriend and his dad have also never have a good relationship and he still doesn’t live with him. My boyfriend (17 M) and I (16 F) have been together for almost 5 months now and have known each other since we first started high school. We introduced our parents at maybe 3-4 months into our relationship and the first time they met ended up with them acting sexual and my mom twerking on his dad. I explained to her that it made me uncomfortable and that I didn’t want them talking anymore. She said she wouldn’t talk to him and after 2 weeks (which within those two weeks she wouldn’t stop talking about him and causing arguments with me) I found out that they were lying and they had been talking and hanging out. My boyfriend and I tried to have a conversation with her about it and all she did was say we were being unfair and made weird comments like “my (p word) is so tight that it is probably closed because I have been with no one because of you and I finally find someone and now yall don’t want me to be happy.” Anyway, it has been bothering me and making me uncomfortable, but they haven’t hung out around me or my boyfriend so I kinda forced myself to accept it. Fast forward to 2 nights ago, me and my boyfriend were coming home from a concert and I get a call from my mom asking how to work something on the tv because her and my dads boyfriend were trying to watch something at our house. We get home and she ends up coming up there and saying he has to stay the night because he “drank too much.” The next day I wake up around 12 and he’s STILL THERE. Me and my boyfriend go fish and hang out and come back around 5 and are met with my mom and my boyfriend’s dad CUDDLING AND KISSING UNDER MY BLANKET. I went upstairs and packed my stuff ready to move out and my mom called me a selfish bitch and went back downstairs to see my boyfriend’s dad. Me and my boyfriend ended up going and getting dinner to cool off in hopes that maybe we would come back and he would be gone, but we got back around 730 and he wasn’t gone. I asked my mom to make him leave and after she went downstairs and talked to him, she came back and told me they were going to watch a movie and then he would leave. Anyway he didn’t end up leaving until like 9pm. Is this weird and disrespectful or am I overreacting? i seriously need an opinion because i feel like im going crazy. Am i being selfish? It is even starting to weigh on me and make me rethink myself and how I should act or if i am in the wrong idk i just am really torn