Tbh I think its a comfort thing and they both want to stay close but not too closeUnless they have an open relationship, and she is ok with him being with other girls I really can't understand it either.
No money, no matter how much I loved him, nothing....no way I was going to through all the cheating.
And getting a kid, as many people seem to believe she is after, won't solve it either. Just look at Hummels, he's been with his wife more than 15 years they have at least a kid (that I know of) and now he has left her for someone younger.
Don't think he has relationship experience either