Another way of looking at this.
If he spends way too much time with her.
Then! I would have to put my foot down on his.
Just to let him know and express how yo think and feel about the whole thing.
Either he reduces his time with her.

( As much as I really do not want to say this)
Or you can arrange it so you can spend even more time with her.
A.K.A. Divorce.
But! If you do!
Take him to the cleaners.
You have tolerated this for so long.
Well you know!

A Woman can only stand so much lack of attention!!