Past is past?

I'm married, have been for almost 3 years now. If you are not married or have been married for 15 plus years, you are probably thinking, 'that's a short time'..and really, it is a short time, however at times it feels like it's been a very long time.
In this foreign land that has been my home for the period I've been married, I've struggled to settle down and fit in. My husband having lived here much longer than I have, had his friends who have now become my friends...some of them atleast, knows his way around and generally is used to and seems to like the life here.
In our long distance dating, I now realize my husband had a section of his life, with another set of friends, a life that was never mentioned. I must admit, he was good at it, good at been silent even when he had lots of exciting things going on in his life, good at never mentioning the concerts attended, the restaurants they ate in, markets visited and walks in the parks, good at creating an image of having a boring life that only involved work and relaxing at home over weekends.
I on the other hand, was naive or stupid.. talking about what I was up to on the other side of the world over weekends, talking about new friends who I thought were so funny. He didn't get to meet all my friends during the times he came to see me but he did at least hear of them.
Is it wrong for me to feel anything about this, should I think it is not necessary or important and was all in the past. Some people are private people, others like me, can't seem to contain it when they have experienced something good or exciting (perhaps this should be in past tense as I have now learnt to keep my mouth shut)
To my surprise, at the end of one of our holidays, I saw something that left no doubt about one of his 'friends' . During a short break up we had, he met a girl and they started to have a relationship that did not end even when we made up. 'Sorry for the overlap' he once said to me.
I got over that and even married him knowing what I knew.
I however wonder what would have happened if roles were reversed.
'Forget about the past' people often preach...however, the past lays the foundation for the future.
Even if I would want to completely forget, how can I , when the 2 of them have now gone into business together.
Perhaps, I will come to see, that I am twice the fool.