(I think woolgather points about Jane is correct)
Lalangela, even though she saw that the emails were harmless, just friendly, started to over react when confronting Joe and became really upset because Joe accused her of being the same as his ex (Jane) in the same situation (Jane got upset about his emails to Sally).
(This part gets a little tricky)
I think several issues are going on:
1. She changed for him but he doesn't change for anyone (my interruptation: she feels that she put more effort in compromising in the relationship mainly that she gave him more space but not getting her needs for closeness met and she accepted this therefore resentment);
2. He retorted that she was at fault and he was going to find someone who will keep him under her thumb (he felt that she was trying to control him and didn't want to go there again; I think he also felt that he was being accused of cheating when he was just being friendly).
I wonder if lalangela was feeling heart broken when she wrote this...for her question does not make sense according to my understanding. Hmmm...looks like I'm going to have to take my previous post back!
Hope this make things clearer but only lalangela can clarify this.