Why do younger men leave their young wives/girlfriends for older women?

Asked by M1952 (301) September 1st, 2014 from iPhone

just a general question?
My husband who is 32 left me (29) for a 39 year old, and I’m just curious as to why a man might do this? Is this something I should always be fearful of? To be left for an older woman in future relationships? Thanks !