My son is 2.5 and I have a daughter that's 11 months old, since she's gotten here my son has been a bit jealous. He's warmed up to her but he hits her constantly and when he's mad at me he'll go after her. He'll hit me and my husband as well, with anything he can get his hands on or with his head, he also bites. His tantrums sometimes last for 20 plus minus and he hyperventilates or almost throws up. How can I stop this? We've tried spanking when he hits her but I don't like it, and don't want to do it, plus it doesn't work. Tried time outs and the breathe method. Lately I've been getting on his level and telling him it's okay to be upset, but not okay to hit. Sometimes this works other times it doesn't. I'm completely lost on what to do. I get so upset because my husband ends up yelling at him and so do I sometimes and that's not what I want to do.