I agree it's needs to be intentional, not reactionary. But finding out about OW #2(3...4...) isn't reactionary, it eye opening to the actual problem. He is a serial cheater and has no desire to change. Also, every decision you make ultimately effects the kids. They will go through everything you go through. They are seeing the mamma's emotions and feeling them. Thankfully, they are young enough so they aren't learning that daddy's behavior is normal.
Don't be afraid to say "you're done" out loud. Only you know if you are. If you are ok with who he is, then keep at it. If not, and you don't either see him wanting to change or don't want to wait the time it will take for him to change (and who knows how long that would be), then why not announce your intentions. Announce it, then move forward. One problem I battle constently is that I don't always stick with the decisions I make (though I know whole heartedly that I NEED to keep them). In the end, I end up getting hurt or walked on.
