I've recently discovered that some men tend to settle in their relationships and proceed to lock down women they feel less than warm and fuzzy about. Perhaps they passed up many opportunities with the women they loved in the past and decided it wasn't the right time to commit.
Or perhaps they realize that time is running out and the 24/7 party bus is sputtering and running out of gas and 40 is around the corner and they have a sudden change of heart. When men lose the oomph of testosterone with age, they tend to lose their higher standards as well.
Funny how when it dawns on them that the game of life isn't to be taken so lightly, it's convenient for them to settle down. Especially if he was a legendary lothario who got his fill of women and he's now realizing he's not immortal like everyone else.