I wasn't going to reply, but look, do you think that lustful evening you had with that girl with the club is going to last every day? You are seeking momentary pleasures. Life is much deeper than this my friend. You have a kid, you owe it the child to be a father to him and a role model. Just my 2 cents. I suggest counseling for your relationship (and don't think it's a few sessions and your good, it seems there are many issues to resolve). In the end if you can't work things out with your gf, then end things respectfully.