usually an A goes south 6-12mths... if not, they it prob means they will staty together (ex lived with a GF when S, then he came back).
Without bitterness, you can ask him to remember that unlike him, the girls are starting to process him leaving the family and dealing with a lot, that it will affect them separately seeing GF so soon and you guys not being divorcd yet. It will be hard, but try to saiy it matter-of-factly so that his thick brain doesn't rule out as being 'too emotional/bitter/jelous'...
The girls aren't stupid and by now might guess what's going on, so if they ask be careful how you address it, don't sound angry or defensive, show them how strong you are.
Be not afraid...I will repay you for the years the locusts have eaten Joel2
30something 2kids survivor of S, MLC, A, D I have peace in my heart, at last.