I need help...

Hi girls. I am really struggling with life in general. So my husband did not heave himself for marriage. He had intercourse when he was 16 with his girlfriend at the time. I thought I could deal with it and as time went on it would get easier. But I can’t get it past me. I have prayed about it over and over but I still struggle with it to this day. I have known since the first week of us dating. But I guess 9 months isn’t long enough for me to get past it. My husband tells me that he is gone and that I don’t need to worry (because I struggle with him comparing me to her when we are having intercourse). I trust him full heartedly. But I can’t shake it off. And I don’t know why. I am not the most innocent either. I did things I am not proud of (but never sex). I need help. It is hurting our marriage, and I just want it to stop.