Have you seen the film Godfather? In it there's a scene where the Godfather is talking to some turkish guy - where the Turkish guy is offering him a **** deal. Eventually one of the Godfathers sons verbally explodes - telling the Turkish guy that he doesn't like what he's offering, thinkis his trade is bad, etc. When the Turkish guy is gone the Godfather turns to his son and tells him off - saying "You should never tell the enemy what you feel. As that gives them the advantage." (paraphrased)
When you approach him, don't tell him there's an issue. Don't mention it - as it shows two things to him:
- HE affects HER
- HE affects YOUR relationship
This gives HIM power over YOU.
Instead what you should do is try to make friends with him. If you're going out to a club - spend some time hanging at the bar with him. Heck let him buy you a few drinks! :cheer: make sure he knows you don't perceive him as a threat at all. If he sees you as mr uber confidant (in regards to your relationship with the girl) he'll back off SO DAMN FAST.
As he's hanging out with your girl allot you'll have to get along with him. Put your hand on his shoulder (he's short after all :crackup: ) and say **** like "Are you looking after my girl when i'm not around?" Follow it with a smile.
This is C+F and makes you seem confident irrespective of his advances. (Althougth you're not admitting they exist) You're touching him so you're the dominant character. You're putting down his status as a man by implyign he's workign for you by 'nannying' her.
And because you're big you'll be naturally imposing.
You'll be alpha - he won't do ****.