Tough Divorce

I'll start off by saying I'm the one who left. We were married almost 6 years, but throughout the time, he was abusive on all levels. About 99% of the time, I am beyond happy I left. Then there's days like today when I feel depressed because we can't even have a normal conversation like adults. I only called him to discuss our taxes, and he starts getting really nasty and hateful. Trying to make me feel bad because our kids are suffering (they're only 4 and 2... they'll bounce back pretty quickly, and they really aren't all that bothered by it. He's just trying to get under my skin and hit me where it hurts). I haven't talked to him in a couple of months, and it's been *amazing* not having to hear him whine and be childish about stuff. But I'm not so good when people say really hurtful things to me like how he's doing.

Any advice on how to just roll with it? He thankfully doesn't have my number so he can't harass me like he has in the past, which makes it much easier to deal with.