Molly, I've been there with at least 4 of my lovers. Sounds like you are in a similar place. You've experienced great sex and you're not going back. I think you have 3 choices: 1) continue behind his back (however, this is not a permanent solution), 2) be honest and tell him how it is going to be if you stay together (which could result in divorce), or 3) simply divorce him. I can tell you that I am currently dating a women in option 1, 2 women in option 2, and 1 opted for the third option. None of them are regretting their decisions. As of those who chose option 2, one is currently still married and one is divorced. The bottom line is you are not going back to inferior sex