I think it's not so much of having a friendship with a guy that is what bothers me about the post, it's that she's communicating with him when she should be working on things with you.
My husband is also the very jealous type and I do have male co-workers that I go to break with etc. But, I don't take time away from my husband to be contacting them, just like I don't take time away from him with my female friends.

I guess I don't think the issue is so much whether she is spending all this time communicating with her friend (it doesn't matter male or female) it's that she isn't working on repairing your marriage...