My first experience in hearing about my wife's sexual past was during my first marriage when my then-wife finally admitted she had fucked with several other guys before marrying me, despite letting me believe she was a virgin, as was I.
When I finally got past my anger and grief and we were able to talk about it, I told her I wanted to know "everything", thinking that it would somehow make it easier to deal with if I knew all the facts.
She was willing to share "everything" and before we were through talking, I knew how many there had been (4), how many times, approximately, each had fucked her, where they had fucked her, exactly what they did together, how naked she had been with them, and very importantly, how "big" they were.
All this had an effect on me I had not expected. It turned me on like I could not have anticipated. Just hearing my wife telling the details of those other guys fucking her just made me want to fuck her even more. So, after that first time, whenever we started getting romantic, I would ask her a question about one of them and she'e give me the details while I was able to form a very realistic visual image of him fucking her.
After that, I was never able to go back to being the kind of husband who valued a woman for her innocence or inexperience. The only woman I could be attracted to was one who had fucked with lots of other guys and who wasn't afraid to admit it.
My present (third) wife has fucked with more guys than she can remember, and I wouldn't have it any other way. She has told me many of her adventures, and I have talked with a few of the guys who fucked her before me, including her first husband. And just like in my first experience with "delayed wife-sharing", it just makes me want to fuck her even more to hear about how some other guy enjoyed her pussy, now MY pussy!