Firstly, you're not alone in never having had an orgasm. Many women never have. In fact, about sixty percent of women have some kind of trouble orgasming. Some of it is inexperience with their own bodies, but much of it isn't. Personally, I didn't have an orgasm for the first five years or so of being sexually active and it definitely had nothing to do with lack of sexual exploration. Actually, I still can't get myself
to the point of orgasm, but with a partner present I can nearly just think myself there by now.
If you don't know exactly what turns you on and how to reach at least some of the stages of female sexual arousal
, it's time to explore. If you feel that you know your own body and sexual responses inside out, though, and still can't reach an orgasm... you're not alone. Identifying what is keeping you from getting there can be useful (e.g. for me, I think: trust and control issues), but it probably won't magically solve it (it still took me years to get to the point where I had what I needed).
I'd also like to suggest that faking it is very helpful. Fake it 'til you make it works elsewhere, but not so much with sex. You're not giving yourself the opportunity to experience pleasure, by quitting without it, and you're teaching your partner(s) that what they're doing is working. There will be no incentive to try to get you off for real, because they think they are.
Now, I know I'm not addressing the feeling of sickness here and that's because I think that you should probably talk to a professional about this. Perhaps start at the maternity ward and find out if they have heard of similar problems. Did you have a traumatic and painful birthing process, for example, that could be triggered for you when you have sex (being that this is ultimately what caused all that pain for you)? They'll have experience with all sorts of things post-pregnancy.
Lastly, I'd suggest being open with your partner about these things. You're not feeling well, it's affecting your marriage, and you've been lying to him about your sexual gratification for a long time. I'd probably not lay it all on him at once, but it's not a path towards a healthy relationship and it'll be easier if you don't have to go through it alone.