E.M.
K.,
I have 3 boys (16, 16 and 5) and they can be a handful sometimes. My advice at this time would be to take a look at how often you or your husband (or son's father) say NO! to him. Or if he is cared for by someone else. Little ones, at that age especially, are sponges and imitates his parents or caregivers. Anytime you want to change what he is doing Do Not shout NO! (THIS DOES NOT MEAN THAT YOU DON'T SHOUT NO! IF HE IS RUNNING TOWARD THE STREET OR PUTTING HIMSELF IN DANGER.)Instead remove him from whatever is going on and give a choice of what would be better to do. IE: saying why don't you play with this puzzle or this book? Or you could play or read with him.
I would not avoid play dates as that will make it even harder for him to socialize. What you need to do the next time you go to one is keep your eye on your son at all times. Be ready to praise him for good behavior and give him your attention if he seems to want it. If no one is playing with him maybe get down and do a puzzle together. A child at some point will come over and want to join in. Slowly get up and let them play but still be on the ready to help if any fighting over a toy begins. At that age I would usually take away the toy that was the problem unless they could agree on other toys. If he is not getting attention when he is behaving, he will learn that fighting over a toy will get your attention fast. Until your son learns to get along with others you need to not get engrossed in conversations with other moms at play dates (I know how easy that can be). Put your focus on your son to help intervene before there is a problem.
Read a chapter or two on Two's (maybe other mom's have some), talk about it with the other mom's you get together with. You might be surprised in the problems that they have had to deal with .
Remember to stay calm, be loving, patient and you will both get through this time.
Hope this helps,
Evelyn