1) Keep your kids close, be honest, listen to them, ask them questions, constantly check with them on their emotional state. Being able to talk through it helps a ton for them. I won't sugar coat it though. First few weeks/months might be tough...for both you and them.

2) Your situation is waaaaaaaaaay more positive than you know. So take refuge in that. You'll be close to the kids, in an agreeable situation where she's not bitter/vindictive and won't struggle-struggle financially (I know it'll be tighter but if you can manage it, you're in a great space).

3) Mourn the loss of the relationship and take a lil time to heal. Don't sulk too much or let anger consume you. She's living her truth and in time you'll realize that's better for both of you than forcing it. This happened so you can find the space you need to be in.

4) I'm on marriage #2 and trust me, it gets better. Mainly because you'll know yourself more and will be much more keen on the type of person you allow into your life. There's a bit more at stake. So if it's serious, you'll vet more thoroughly. And if it's not, you'll make sure there are clear boundaries.

5) Make your ex accountable but not at the expense of the kids. There will be times where she's trying to unload them on you during 'her' time. As a dad, your first instinct will be to clamor for that extra time, but at the same time, be careful not to enable her. If you're doing more work, why should it be a 50/50 split of responsibility? Make sure she pulls her weight or pays for it. One or the other, no in between.

6) Lastly, my condolences. I know it's tough but trust me, you can come through the other end a better everything...husband/mate, father, person, lover...etc. This trial is not too great to overcome.