If you two are engaged, he may want to make sure his feelings for her are over, because marriage is a giant step, and it's important to know that past loves are completely over. Marriage on the horizon sometimes causes a person to think about every person in their lives and what that person meant to them.

He may be keeping it from you because he doesn't want to hurt you. I know, truth is better, but some of us can't handle the truth very well. Sometimes truth is uncomfortable, so people who love us, think perhaps it's better we don't know.

I'm not sure how you found out about this, but if you have some secret way of knowing what he's doing without him knowing that you can, perhaps you had your doubts before.

As another poster said, better to find out what you are dealing with now before you get married. Coupledom is a tough road, especially if we have friends of the opposite sex, who may or may not be seen as a threat to our relationships. If he likes to have friends of both sexes, then you must decide if that's something you can handle.

Choices, it's all about choices.