Reading the other comments, I think I read less into the line "she doesn't want to share me with anyone" than everyone else did. Which is probably an indication that I got it wrong, and I'll accept that. But the way I saw it was less that Dawn is actively trying to break up the LW and his kids, since he doesn't really give any examples of stuff she did--rather, that she's expressed these feelings to him. I totally didn't come to the same conclusion that she has taken steps to try to cut them off from him (which would, yes, be despicable). And there is the possibility that if this has been going on for a while, LW was feeling pressure in that direction even if she didn't explicitly say more than that.

Anyhoo, it's purely a matter of interpretation of a poorly-described situation on the internet and I agree with the sentiments of everyone else if the facts are as they're saying they are, so I'll leave it at that and step out here.