Past Encounters

Hi guys!

I believe in waiting untill marriage, and my fiance was raised the same way. He told me he had done things with someone else once before him and I dated and that he regretted it right away and it was a huge mistake, then once we were engaged he told me he had actually had encounters with that person multiple times.

Besides this, he treats me great. I love him so much and I want nothing more than to feel okay but I don't know how to get passed it. Advice?