Anal for men ? Please read ! Advice needed.

Okay so I don’t usually like outside opinions on my relationship but I’m at a loss rn. So me and my boyfriend have been together for around 3 months now and I have honestly never been happier. He is my dream man and I love everything about him... now. For some background, towards the beginning of our relationship (the 3 months of talking before we officially started dating) I wasn’t really sexually attracted to him. To be completely honest, I almost felt uncomfortable to even think dirty about him. I think it was because I just don’t like being chased. When a guy chases me it’s a total turn off and it kinda pushes me away. I told myself it was only in my head since I have a tendency to push away the good guys. And it worked ! I got past that and fell head over heels for this man. Our sex life is amazing. He knows my body almost perfectly and being in love w him makes it 1000x better. We’re also more adventurous in bed than I had been before. We bought lube, a small vibrator and a little butt plug. I wanted the vibrator and he wanted to try the butt plug on me because he had been wanting to try anal and I was open to it. So we had experimented a few times and it’s just not for me. I can’t get into it, I can’t cum unless I used the vibrator and after I cum I just want him to stop. He didn’t mind because he said he likes vaginal better anyways. Then the other night we were talking and he confessed that he had tried my butt plug on himself and that he liked it and he came in like 2 seconds. And I just can’t. I don’t know why but I just cannot stand the thought of him jacking off in the first place, let alone putting something in his butt and him enjoying it so much. I know every one masterbates. I know that. I’m not saying I don’t expect him to do it, I just don’t want to know about it. I have never been comfortable w hearing about my significant other masturbating unless i was somehow involved like phone sex etc. I think that’s the part that is messing w my head so much and I just don’t know why. Maybe I think he thinks about someone else ? Or watches porn ? But I do too. I mean I used to watch porn before we started dating. It could also have something to do w my ex after I walked in on him doing himself in the bathroom when I was in the next room. But it’s also freaking me out that he liked something inside of him. I know the male g-spot is in their butt, I get that. I had talked to my sister because her boyfriend is into that stuff to and she said she wasn’t comfortable w it at first either but it quickly passed. I guess my question is how do you get comfortable w that ? I know I’m nowhere near ready for him to bring it into bed w us but I just want to stop picturing him doing that to himself(using a butt plug). I think it’s disgusting tbh. I think it’s wrong for some reason. I’m the farthest person from homophobic, I have plenty of gay friends and it doesn’t bother me a single bit. I’ve been w plenty of women as well. But I think it’s different thinking about the man I’m w like that kind of stuff. But I also don’t want him to feel embarrassed for telling me or that it was wrong. I want him to be able to tell me anything. I’m not judging him, but it does make me uncomfortable and I don’t know how to make it go away. We have joked about it all the time, like I would walk past him and stick my finger on his butt just to mess w him and he would say “hey ! Get outta there” or “I might like it” and I thought I would be more open to him doing that but now that he told me he already has without telling me, it’s just stuck in my head. And I hate it. It’s making me feel the way I did before we got together where it was like I was uncomfortable to have sex w him kinda. Ladies who have experienced this or are comfortable w it, SEND HELP. 😖