I think the line you've taken so far has been honorable. You probably shouldn't dwell on the smirking feeling, since that might pollute your intentions. It's not wrong or jerky to feel something, since I don't think people can help but feel things, but it is your responsibility to respond appropriately to those feelings, meaning it might be poor judgment to focus on the smirky sensations you get.
Also, to the extent you can, I'd say you should encourage her and her husband to work things out, because if she broke up with him and hooked up again with someone else, there is always the possibility of her breaking up again. Though it sounds like it is her husband's fault at this point, if a woman breaks up without dang good reason, then be careful about the weight of that woman's commitments. I don't know much about the situation though, so my opinion is general and may not speak to the issue at hand. I personally hold the conservative standard that a person in general should not divorce his or her spouse unless there is adultery or abuse going on. But what do I know? I'm not married... yet.