Taking care of the kids is not letting her lean on you as an H, it is being a good parent to your kids. That's not something you want to change. You want to be as available to help with the kids as you can. They need both of you, and there is nothing more attractive to your W as you being a good dad (esp. when you just get on their level and allow yourself childlike play with them).

Don't make demands on her or expect things from her that you would just expect as part of your H-W relationship. Don't jump in and take care of things that you always have to fix her problems. If she asks for help, give it consideration. Is it something friends would do for each other? Fine. Is it something expected in an M? Really think about it. Is she expecting things without reciprocating or consideration? Is she still doing some things as your W that for which what she is asking is a kind of reciprocation?

Me: 50 W:43
S6, S3
M: 12 yrs. T: 17
M is bad & Not happy Bomb Mar '14
S 5 Feb '15
D Bomb 13 Apr '15 (but "no hurry")
DB Coach May '15
Wants proceed on D Aug '15
Starting 1-on-1 negotiations Sept '15