Had a former best mate who was exactly like this, and no, i'm not jealous, the bird was pushin 120kgs, total ugger and an absolute bitch to boot! I tried and tried for over a year to convince him to stand up for himself to no avail.
Then she broke up with him and who did he come to for a bitch and moan, I thought "awesome, he's dodged a bullet", back together after a month of her screwin around and gave up on him after that.
Left it to him to contact me when he wanted to catch up, final straw was when I was in hospital for two weeks after a stroke 2 years ago and his mum rang to see how i was, but he never contacted me or visited, true colours came through. Needless to say, still havent spoken, goin on 3 years.
So my advice, give up on him!! He'll have to grovel to his mates when she gives him the flick, so just wait for that day to come, say I told you so, fuck off, and move on over a few beers