Dislike my girlfriends kid

DO NOT MAKE A GIRL CHOOSE BETWEEN YOU AND HER KID!!!

If you can't accept the kid that's fine, you are under no obligation to do so but you don't have the right to get between parent and child either.
If you can't accept her kids then you need to move on and end the relationship.

A parents responsibility is their child first and foremost always.

"I told her yesterday I can't accept him nor want him to move in to my home."

Yeah, you know the kid will always come before you right? You can't make her choose. You can either put up with the kid or break up.

Maybe she's not the one for you?

You need to grow up: if the kid has been in foster care he obviously will have problems and if you can't deal with that and be an adult about it, do your gf a favour and don't marry or move in with her and her kids.

I've dated women with kids, and, gotta be honest..Maybe liked 2 of them (kids). One I dated still had her 11 year old daughter sleeping in the same bed with her, which I found incredibly odd, another wanted she and her troubled 8 year old son to move in with me after the first 2 dates, and another had a 3 and 4 year old who were so annoying that I left their apartment.

It's fairly clear, I need to be with women without kids, or, if they do have them, older or on their own. One had a smoking hot, college-aged daughter that had me looking up and down to not stare at her perfect body (was a Charlie Sheen, Two and a Half Men moment). Had to break up with her just because I would have gravitated towards the college girl. And had her.

I know what you are going through. I'm dealing with a disrespectful lazy 12 year old girl, who is sneeky and constantly disobedient, she is rude and show an I don't care additives, her brothers is the total opposite but he is lazy to and looks like he is on his way to an eating disorder. Her daughter said she hates me because I took her mom away, pathetic. I replied to her the PlayStation took her away from her mom, and besides I have a new born with my girl friend. I grew up in a strict house hold, their were consequences for my every action. I talked to my therapist about what's going on. She told me it's the mother's fault for not being firm and making excuses to defend them for misbehavior. Her kids are here I'm dealing with only my daughter. I can tell you how many times I said to myself I don't got to deal with this crap, but I love my girl friend. I remember a biblical scripture that says " Children be obedient to your parent's in union with the Lord, for this is rightious and may go well with you and you may endure a long time on the earth" also spared the rod spoil the child, the rod is a metaphors for knowledge not a beating even though some kids need a good one like the many I got. If the mom is ignoring her responsibility it will come back to bite her in the butt, you will then hear her say, I should have been more strict, should of could of. Love is the key, patient and Lon suffering. Some time no matter how much things get on your nerves, you got to let it go, it's really not your problem no matter how much it seems to be, the mother needs to get pass denial and parent up before she looses a good man.

All I´m seeing is that he listens to music when he´s at your place? Why is this such a horrible thing? Does he steal from you? break your stuff? do something illegal?

From his point of view you are an intruder that tries to get in the way of his life.

You should not move in together until HE accepts you, forcing it on him and demanding that he will respect you? That´s fucked up.

Earn his respect, set out clear rules. He can listen to music all he wants but he must be home on time etc etc ...

You should never expect a parent to pick you over their kids, and if they do? The two of you deserve one another.

I had a very similar situation to this. My wife had 3 kids prior to us getting married two girls who were ages 2 and 8 when we met and and a boy who was 12 at the time. The boy was pretty much the same as your girlfriends kid. Lied about everything taking stuff that didn't belong to him screwing up in school. Don't like to say it but I hated that kid. I did everything I could to make him comfortable got him pretty much whatever he wanted. I tried to help him with whatever he wanted to do but nothing worked. I had to put up with his shit for 7 years until a few months ago when he finally gave me a semi legit reason to put his ass out. I would still help him with anything he's trying to do to better himself. But I refuse to let him sit in my house and not do nothing. My advice to you would be don't marry her right now. Remember the woman and kids are a package deal and you'll be stuck in that situation miserable at least until he's 18 and probably a little longer. No matter how much you love your girlfriend/wife trust me your dislike for him will eventually weigh negatively on your relationship. I've been there and done that trust me.