After the honeymoon and the passion come insecurity and self doubt. Finding out about a spouses past is an inevitable part of learning about each other. There might be less conversations about this than other things, but it is bound to come up either directly or indirectly.

There might be thoughts of jealousy if you find out what sort of torrid affairs or you might have insecurity because of the number of lovers or the strength of the passion. They might want to pressure you into doing things you don't want to do because someone else did it. This really shouldn't be done, but I know us guys might try it as leverage.

The fact is that the spouse chose you to spend the rest of their (hopefully) life with forsaking all others in a major commitment. If they had these feeling that were still legitimate or strong they wouldn't have chosen you, they would have chosen another person. It is possible that the feelings of insecurity and jealousy could get in the way of a real and trusting relationship, they need to be let go.

They might be thinking about a past lover from time to time, but can you really say you never do. that doesn't mean that you have any intentions to do anything, does it? So don't worry, the past is the past.