Honestly, I don't think there is anything YOU can do to change things. It's really not your job to make peace 'for your husband's sake' because your husband has been part of the problem in creating the monster. He allowed his ex to never say no... I'm sure that started when they were together unless they split when the baby was born. But, it's not really about assigning blame at this point... my point is that it isn't YOUR problem. If you have been married and in this boy's life as the primary home for the last 16 years... I would have addressed the problems 15 years ago, not when he's 20.

Your options at this point are to not invite him or put up with him when he's there. He behaves that way because he's been allowed to behave that way for 20 years. My son was a high strung kid by personality... he threw tantrums and was difficult all his life. It was tough. He threw fits at anyone's birthday party when they sang to the birthday kid because it wasn't him. He ran away from me in public places, like on Halloween he decided he didn't like something I said and took off running and once we were in a city and he didn't want to leave a restaurant and ran several blocks... his behavior was not because he had no discipline, it was part of his personality. I didn't have those problems with any of the other kids. It was not lack of discipline and over the years, he outgrew the fits because we did not give it any attention. When he was younger, I would remove him from the situation when he acted up. As he got older and had the ability to understand better, I would tell him prior, that if he acted up he would be removed... then I had to follow through if he did. It wasn't fair to others that we had to go home because he was acting up but once he realized it would happen every time... it got better. Unfortunately, I believe it's part of his personality so sometimes he just acts out without thinking. Now, he's 22 and rarely has a fit but he does have a temper still. He is head strong but he is not unpleasant to be around anymore.

If you want him there with his dad but you don't want to go through last year all over again, I would suggest you take a mini vacation alone. You are not going to change this boy at 20... all you and his father can do now is create a boundary with him and let him know he is not welcome if he is going to behave that way in your house... then follow through. He knows nobody is going to follow through.. that's why he said he's leaving but didn't leave. My son has done that too, he waits for someone to get upset and tell him to stay or let it go. I would have held him to it.. you said you are going to leave, I'm waiting for you to leave! I know it makes it unpleasant for everyone else and you, but you've already endured years of unpleasant and it won't go away until you do something about it. It will continue to be unpleasant until he is held accountable for his actions and the unpleasant behavior is no...

I wonder if he has some kind of mental illness or at least emotional impairment that he cannot control. He is 20, shouldn't be throwing tantrums in front of other people. Well DD21 sometimes get moody with me or her dad, but wouldn't do it in front of anyone else, especially not at the party. She did when she was younger on few occassions in front of others, and yes like imamommy said she was removed. But certainly she wouldn't do it now, grown up.

Possibly your SS is either having emotional difficulties or he is poorly adjusted due to lack of discipline. Even if it is his personality, at age 20 he should be able to control it at a party. If he refuses to behave he should leave or maybe not come over at all until he behaves. i think he needs intervention, his dad telling him that if he acts this way he is to immidiatelly leave.

You have 3 options around holidays. I know it soudns extreme but option 1: is to not invite him over. Option 2: he comes visits his father but you leave the house on vacation, visiting your side of the family etc Option 3: invite him over but the minute he misbehaves he MUST leave.

I think wiht my character i would not be able to kick him out or not invite him, so i would just let dad deal with him and go visit my family members for holidays. If your Dh doesn't like it, then he is the one to put a stop to it.

He's an adult. Treat him as such. Doesn't matter what relation he has to anyone. He behaves out of line, he's asked to leave. I've told my father ot get out of my house. Respect is respect.
And hate to bring this up, but the last time someone was rude and loud and obnoxious he turned out to be a powder sniffer if you know what i mean.???
Tantrums at his age is just not normal.
And can you clarify what exactly did he cause trouble with the younger kids?? What did he do?

I was married to my husband 30 years when I decided this is my home too, I've earned it simply by being gracious to selfish, neglectful children, mine and his. I stopped fixing Turkey dinner complete with everything. I started serving sandwiches, later just finger foods. The final straw was when I asked his daughter's to spend one night in the hospital with their dad so I could get some rest. My blood pressure was out of control because of worry. they came up with excuses. I went home to shower and change, packed all their pictures away. when my husband told me he didn't remember much about his hospital stay and asked what happened, I told him. I told him about his health problems and about asking his kids to help me. He apologized to me for their behavior, and said I didn't have to spend time with them anymore. Suited me just fine.