I feel your pain. Let me start by saying that I am new here. My background seems to be fairly similar. I was physically/mentally/sexually abused by my first husband, and sexually abused by relatives in my teen years. Then I met my husband...who is my world. Protector of me and mine from anything and everything. There is no doubt in my mind he truly loves me. None!!
However....we...who I believe are soulmates...finish each other sentences...love to spend all our free time together...that type of stuff...had problems that, after 15 years of being together, accumulated in him cheating on me. I found out 3 days before Halloween last year...and I had no clue...none. I knew we were busy, but him doing this completely blindsided me.
I tell you this in a hope to say I feel where you are coming from. I read your post and it struck a chord in me.
After things that have happened in the past with me, I told him I was leaving. I believe anyone doing something like this once, either has done it in the past, or will definately do this again.
He has been nothing but supportive. Not just saying he is sorry, which I believe he truly is, but giving me full access into anything and everything he has. I now have all logins to anything and everything he has. Even to login to his work computer desktop.
So my question is this...what has he done to make you feel like this is over. That it will never happen again. That this was a one time thing...and will NEVER happen again?
And yes, my husband tried to minimize it by not telling me everything that happened at first...tried to "ease my mind" by lying even more...but he eventually caved and told me (I hope) everything. So him lying to you about how long it had been going on, could possibly be him just trying to not hurt the one he loves...which is you.