Not so much about morality, as STANDARDS. They may be nice to look at, but lack of maturity, and inexperience of a younger woman leaves a lot to be desired. There are some things you just can't teach.
You don't have to marry her.
I'm married, so it's a moot point, but if I was single and Kate Upton walked up to me in a bar and handed me her hotel room key, I sure as hell wouldn't hurt my brain evaluating her maturity or inexperience. If anything, I'd probably knock myself out by tripping over my feet trying to get there too fast.
I'm just sayin'.