If you had a friend who never had a girlfriend and he gets one

If you had a friend who never had a girlfriend and he gets one (obviously he will start acting differently towards you and not talk to you as much as he used to) would you want his relationship to go well or his girlfriend to give him a personality development so he can mature as a person? (his girlfriend emotionally destroys him and leaves)

Remove the "obviously" part. I had a lot of friends who didn't change a bit even after marriage.
If the friend puts you at the end of his priority list, he never was a real friend to begin with.
I would wish him the best and hope he will be able to manage the relationship.
If he'll get "morally beaten" by his girl, he has problems...