Off and on TRP.

Been in LTR almost 6 yrs, 4 living together. Me 35, her 31. First 4 years together were the best years of my life, and hers too. We didn't see anything except each other, pure connection, love, understanding. She cooked, cleaned, great sex, the whole 9 yards. However I wanted to get married, she wasn't ready..this created fear of loosing her and anger in me, and our relationship took a strain. I did things I'm not proud of (controlling, wasn't happy with her going out with friends, even not that often, was asshole to her and her friends) but she stuck with me for another year. I would never budge in any of the major decisions, our future..it was my way or the highway. Eventually we decided to call it quits because I was too controlling..and she wouldn't marry as things weren't right between us. I wanted a stay home wife and she wanted just a little bit of freedom to go out with friends, have some say in decisions making process etc. It's been 3 months and I think I've made the biggest mistake of my life, being controlling asshole without compromising anything. No contact since the breakup. I was broken. Eventually, she contacted me and we met. She said she misses me and can't cope, wants things how they were in the begining. When I was manly, friendly, sure of myself and kind. She wants to try to take things slow and would like to see if I've changed. When I've asked about her sleeping with someone she said she will not explain herself as it's none of my business what happened during our breakup and she does not want to know if I have slept with anyone during that time either) The issue: I would like to try and see how things go..meet up a few times and see if we can rekindle the feelings however the biggest thing that bothers me is her sleeping with someone (she didn't deny it, meaning she did. I didn't sleep with anyone-i was to heartbroken). Will I be able to get over this? Should I even try? Would me sleeping with someone now prior to getting back together help? Or even tell her this that I would like to do this? Should I decide to try, should I tell her that because of this issue I can't guarantee that this will work? That knowing this..or not knowing how many, with who..may literally drive me nuts? Is she right? Is this my problem alone?

The reason why this is such a huge deal for me is because my first high school love cheated on me and got cought. Since then, this has been the biggest fear in my life. I know, by Today's standards girls have had 20-30 guys etc, everyone is screwing and it's normal. Am I overreacting? What should I do? What would you do in my situation?