I had some thoughts about your H's email that might be a little more positive than how it made you feel. If she's been emailing your H lately and trying to drag him back in, his comments would make sense from that point of view. He didnt have to be *involved* with her. For instance.. when he says "she's losing me" and it sounds present tense, he might be talking from her perspective. If she never really let go, or is trying to reattach (even though he hasnt), it kinda makes sense to say that in the present tense. And he says she'll be after new prey and won't remember his name in a few months. Maybe he sees this new communication as just that.... her being through with her BF and running to him and he knows since she's rejected, she'll just move on to the next man.
I have no more idea what's going on with your H than you do, and would've probably thought/felt the same things from that email. She really did re-enter if she started communicating again, but that doesnt mean your H took the bait, and him rejecting her would be another ending of sorts.