You've put yourself between the proverbial rock and a hard place. I'm so sorry, depressedgirl. If you're not physically/sexually attracted to him now--when?
I'm not sure the issue at this point goes any further than this one relationship. Even if you're 100% heterosexual, marrying
this particular man is throwing up all sorts of red flags at many levels. Figure whether you want to spend the rest of your life with him, raising the children you have with him. If you don't, end the engagement.
Then move on to you and start discovering for real what your sexual preferences are. (By the way, do you really need the props ... now that you've gotten this far?--I hope not)

roadie