my sons father..

Hey, was just wondering if someone could shed abit of light on my situation - hopefully someone has been in a situation like mine or close to it. My sons father and I are no longer together - he cheated on me 7months pregnant, he's still with this girl and lives with her. He sees my son twice a week - by his choice. He wants our son Alfie to go to his house but refuses to give me his address & he also wants alfie to meet his partner, both I've said no to. He's gone to solicitors about the matter & I'm due to go thursday to see mine. Alfies dad smokes weed, has a gbh charge, can't put a nappy on alfie, let's him sit at the top of the stairs alone, smash glass..and much more stuff he's not capable of. Do I have the rigjht - being alfies mom - to say I don't want his partner meeting alfie? & if it was to go to court what do u think will happen? Thanks