Is husband too close to female friend?

My husband is very friendly with a woman he works with, he left his job last week and went out for a drink with what I thought were his colleagues. It turns out it was just him and this woman. He did tell me himself and I tried to be ok with it. However I just couldn't shake the feeling there was more to it. I ended up looking at their messages to each other on his iPad and they seemed over friendly but nothing sexual just lots of kisses etc. The one that did worry me was last night when she text "love yaxxxx" and he replied "love you xxx". At this point I couldn't leave it and spoke to him about my concerns. He swore nothing was going on and they are just very good friends. Now he's saying he won't speak to her anymore if that's what I want. Will that make me the bad guy? I also know she is having problems with her fiancé and I feel she wants more from my husband as she confides in him about her fiancé but he says he doesn't feel that way about her. I really don't want to dictate who he can be friends with, but I feel she wants more from him and he is encouraging her by being so friendly.

He does want me to get to know her, but I feel if I do and she is trying to make a move on him, I would feel like a complete mug. But on the other hand, as the saying goes, keep your friends close md your enemies closer.