I'm feeling super bad please answer me

I already made a post about it, I don't have orgasms like I used to anymore, and it's destroying my couple..

At the beginning of my relationship, everything was good, I had orgasms with penetration nearly each time.

Today, it's been nearly nine months that we're together and I regret this time...

Today and since maybe 5 months, I don't orgasm with penetration anymore, but to me it's essential and it's really bothering me... Even tough I orgasm by myself or by oral sex, I can't help but feel bad about my sex life.

We've talked together about it and he said he would try some things to make things like they were before but it obviously didn't worked out... So I find myself telling him way too often that I feel bad about our sex life, and because of that he thinks that I deserve better than him and that I should find a guy that pleasure me unlike him. It's hurting me so bad because a while ago I taught about cheating on me, I'm the bad person there I know, but now I just want to get things better with him I don't want anybody else. We've tried things but nothing worked out so I'm starting to losing hope of it getting better...

I tried to think about all the things that have changed that could have an influence on our sex life... What changed is that I'm on the pill now, and it's seems like the "non orgasm" period has begun around when I tlstarted taking it, I don't if it's related but that's in fact what happened, I also gained some weight around this time...

Did it ever happened to anyone?

Can you help me to escape this fear of it never getting better?

What do you think I should do, please help me...

Ps: I was his first, and he was mine too, so we don't have any over experiences... (This is mostly the reason why I thought of cheating on him)