What do you think??

I had an interesting discussion with my husband last night. Andrew had prayed that a certain boy that sometimes is at the park would be nice to him. I told my husband about that and he started talking about another little boy that had bit Andrew a few months ago. We'll call that little boy K. K would have problems only when Andrew would go over to his house. Very possessive and controlling to Andrew when he was over. But when K was at our house or when they boys were at the park there was never any problems, other than the normal stuff between little boys. So, Matt was saying how he doesn't want our kids to think that they should be friends with people that abuse them. I responded saying that I don't think one little boy biting another little boy ONCE classifies as abuse. Boys are very physical. K had punched him once too. But how many times has Andrew hit Lucy?? Anyway, Matt disagreed siting an abusive husband shouldn't be gone back to, even if he's only hit the wife once. I think that is COMPLETELY different than two 5 year old little boys who are learning how to control their bodies and how to treat others around them. Back when the incident occurred, Matt didn't want Andrew going back to their house. Which he hasn't. K hasn't been over here either. But they were gone for a while too. Anyway, my question is what do you consider abusive behavior in small children? Would you keep your kids from playing with other kids when there has only been one or two incidents? Matt was the youngest in his family and hasn't really been around kids very much. Whereas I am the oldest of six kids, babysat a ton growing up and I feel like I am a pretty good judge of who my kids can play with and who they can't. I have a feeling that this might cause some conflict in the future, so I was wondering about any experiences all of you have had and how you dealt with them. I feel like if I'm going to be able to change Matt's mind or at least give him a different perspective I should be well prepared with some really good arguments........