Bottom in desperate need of advice?

Hello there. First time posting here.I have been in a long term relationship for over five years and we have had very difficult "cycles" in our relationship because of sex.My boyfriend is a top and he really likes sex, is very kinky, very eager and all that. I'm a bottom, kind of a dick pig but most of the time I'm not.Spanning our relationship's lengthy life we've probably had penetrative sex like 10 times. I know some of you will say OMG how is this even possible you are lying. But it's true. And it's my fault.I don't want to go too into it, but I had a rough coming out experience which prompted me to actively stay as far away from penetrative sex as possible. When I did start to get over that and become interested in it, I was already too broken to function normally I guess.So here is my problem: I am very uptight and take myself too seriously. I do not judge people other than myself. Most of my friends are disgusting and I fully support and admire them.Examples: I cannot fart in public. I will endure twenty hours of gas pain if I have to, until I can get home and fart inside my very own bathroom. I couldn't pee outside my house until I was 18 and had to choose between peeing in a public bathroom or peeing over myself. I am kind of a nutjob and I have already stablished with my therapist that it all traces back to my coming out experience, which triggered a need to portray myself as nothing less than perfect.This was all my introduction section. Now that you know how fucked up I am, let's go to the issue at hand.I love bottoming but I hate having sex.To me, it's all very simple and logical. I cannot allow myself to get impaled by my boyfriend's gorgeous dick - or any dick - if I can't be 100% sure that there's only pure atmospheric air inside me. I dread the thought of leaking anything during sex. The only times we had sex I literally didn't eat for a couple of days, spent over 3 hours douching or a combination of both. I need at least a 72h notice before thinking about having sex.The other issue is: I love nothing else more than I love eating. So you can see what the problem is here. I have to deliberately stop doing something that is not only my biggest pleasure, but an essential part of living in order to find peace of mind to spread my legs.It's painful. My boyfriend says he doesn't care that I'm squeaky clean, that he knows he's fucking ass and not a bottle of perfume, etc., but to me it doesn't matter because I feel uncomfortable and awful if I try to do it spontaneously.Every damn time we argue it's the same thing. I'm very affectionate, so I expect at least some affection back. At some point he just makes me feel like shit in that department. I spend weeks trying to figure out what's wrong and when I do, he's frustrated because "we're just best friends, not boyfriends, and I wanna be both". I suck it up, starve myself, have sex, all's back to fairy tale standards, then I can't keep up with the starving, so he starts starving himself sexually until we're back where we started.I don't know what else to do. My therapist asked me "are you sure you REALLY need to go through all these procedures just to have sex?" and I figured out I DON'T KNOW. I've been taught by the internet that I should so I'm trying to go full circle here and ask the internet if I misinterpreted the whole thing and there's actually a way to bottom frequently without starving myself and having an obscene water bill.I researched a little about fiber supplements and people that just have a balanced diet and bottom just fine but I felt like none of the cases addressed my issues accurately enough to make me feel confident about the answers.So please, I beg you, help me! Am I sexing wrong? Any help is appreciated. Thanks in advance.PS: Another thing that I noticed is that I can take several inches of dick like a pro if I'm in my ideal cleanliness levels, but if somehow I missed a tiny insignificant poop in there my ass flares up and it feels REALLY awful, like it's burning for real. Then I ask for a break, go to the bathroom, eliminate that little shit and proceed to take the D happy and pain free. If just the smallest shit can have this horrible effect, how come some people can bottom pleasurably without this much preparation?