This is embarrassing and dumb

Here is the problem I have a crush on a coworker. It seemed pretty innocent enough. I didn't flirt but we talked and we could laugh. It seemed like I liked him more than me which usually happens. Either I enjoy someone's company more than they enjoy mine or someone lusts after me and I don't return the feelings. However it turns out they might like me back and instead of being excited I had internal dread. I knew sex was going to be a thing in the future it always is. It's a necessity in any relationship wether it's serious or not. I'm not in relationships because I'm not interested in sex. Honestly it feels like I should never bother. I don't have much to give already and I feel like taking away such a "needed" part of a relationship is selfish. It's stupid but when I was told that they like me back I went to the bathroom and cried. I just can't give them that. I can't be with someone I genuinely like because I can't make myself perform a basic function that everyone can do. I don't know if it's depression or a sex disorder or what but I got genuinely upset. I just wanted to talk about it because this situation is so embarrassing and awkward and I have no one to talk about it with.