A)He is gorgeous. Do we need more??
B)I assume Owen already broke up with the guy, making it easier to forgive her. He also needed a kinda big favor from her on short notice, so he kinda had to forgive her. Or maybe he just realized "Yeah, this guy does seem bad!" and dumped him.

I also noticed that both times Kalinda met with Bishop they were wearing the same color. Purples the first, blue the second. It's a subtle way to hint at the audience they are connected somehow.

Bored of not being on tv? He's acted in and directed many plays in the past 10 years. I assume he's very happy going back to being a theatre actor and not at all bored.

He's doing Cabaret on Broadway and needs to have dark hair for that role. The Good Wife has basically put white makeup on it in places to gray him up a bit so it would be less drastic. If you look back at the last few episodes of season 5, his hair got dark seemingly overnight.