In my years, I have heard many little stories about men who have sex with as many women as possible before marriage, but when he is married, changes and remains faithful. Some men call it "getting it out your system." However, I have never met a man who was faithful to his wife after having a promiscuous past. I call these men "rolling stones." Is it possible for a man with this type of past to be faithful? Because most men are unfaithful; few are faithful.
The only time that would be true is if the man had a dramatic, radical change in giving up his life of sin. The idea that someone can get involved in sin to "get it out of his system" is false. A angry man doesn't get rid of anger by indulging in it until he gets it out of his system. A thief doesn't steal until he no longer feels like stealing.
But I've know drunkards who have stopped drinking, not because they had indulged in it, but because they realized how wrong it was and radically changed. I've know people who had been involved in sexual sins who stopped because they realized they were wrong. "And such were some of you. But you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus and by the Spirit of our God" (I Corinthians 6:11). The key is in their current attitude and actions in regards to sin. If you expect a man to settle down after marriage, you'll be sadly disappointed. But if you find a man who is committed to the Lord now and uncompromising in his commitment not to sin sexually, then past failures is not a major issue.