Howdy SAHD! We can't seem to stay away from here can we?
I second, third, or fourth what everyone else has stated. Especially since it's what I have been doing.
Your kids (mainly the older one) are getting to the age where the sitch is going to start affecting how they view a marital R. I noticed this in my own kids. I had to stand up for myself and show them that what was going on was not acceptable M behavior anymore. Right or wrong I had to file for D for the sake of the kids. W was putting the kids in situations that were embarrassing and shameful to D10, and S6 was starting to grasp the sitch so he wasn't far behind his sister.
You don't have to file but it's time to stand up and find a way to move on and show those kids that their dad is Superdad! As you know W and OM are in la-la land just having a "good time". Keeping the status quo any longer is just playing into their hands.