My experience is only of kids in childcare, but it is that it does get better with time. They need lots of physical and emotional outlets in their play - playdough is a really good one because it promotes talking, but also allows punching, pulling, stretching etc. Ditto ball games, and anything else you know that involves a lot of yelling.

It's your loss too, though, and that makes it even harder for both of you. You'll get him through, you're a great mum. All the time.