Is This Wrong? or Am I Being over Protective?

You are not being over protective the step mom is. In my opinion she is way over the top here. You son hugged his sister maybe a bit too tight but we don't know the circumstances around this action. Does this woman take her children to the doctor for every little bump and bruise? If so she's a nut case.
You need to talk to your ex and get him involved in this situation. He needs to treat all of the children fairly and equally. If this is not possible then I think you son should live with you and see his dad on weekends.

Why don't you call your ex husband and speak with him about this? It seems like you're only getting your son's side of the story so how do you know what's really going on? Not saying he's lying but he's TWELVE and chances are there's more going on than you know.

That sounds like a really tough situation. But remember you are only hearing one side of the story. There's probably a lot more detail within the relationship dynamic that is causing your son's step mom to act like this.

I suggest you meet with your ex for coffee or breakfast or something to talk about what's going on. Step mom could join too, if you have had a decent enough relationship. But if things were already tense or strained between you and step mom, it would probably be better to meet your ex alone.

For now, can you take your son for awhile during the time the party is going on? He's going to be disappointed for sure. But I think you're going to have to honor this request for space right now before you can all move forward. Your son will be OK missing one party. It doesn't have to ruin a longer term relationship with his sisters. It would be good for you to have a heart to heart with him about actions sometimes having longer and further reaching consequences. He can't change the past, but he may have to accept it's just going to take time and a decent track record of non-violent behavior to build trust back

Updated

That sounds like a really tough situation. But remember you are only hearing one side of the story. There's probably a lot more detail within the relationship dynamic that is causing your son's step mom to act like this.

I suggest you meet with your ex for coffee or breakfast or something to talk about what's going on. Step mom could join too, if you have had a decent enough relationship. But if things were already tense or strained between you and step mom, it would probably be better to meet your ex alone.

For now, can you take your son for awhile during the time the party is going on? He's going to be disappointed for sure. But I think you're going to have to honor this request for space right now before you can all move forward. Your son will be OK missing one party. It doesn't have to ruin a longer term relationship with his sisters. It would be good for you to have a heart to heart with him about actions sometimes having longer and further reaching consequences. He can't change the past, but he may have to accept it's just going to take time and a decent track record of non-violent behavior to build trust back

Your question posted twice. Apparently my answer is posted in the question posted last please read it. I gave your situation some thought. I have a grandson who has anger issues and squeezes his sisters to hard.

answered on the double to this question.
khairete
S.