On a practical note, don't feel you need to give him what he wants, sexually.
If you feel that you are being manipulated, you probably are.
I certainly was. I look back with huge shame and boiling anger that I did things which made me feel awful, to keep the peace.
Grey rock him as much as possible. Poker face, don't react. Just ignore/walk away.
TBH, I think, if it is going the same way as mine, then there will be a tipping point, and he will leave you.
Unless you are working like a demon right now, to set you and the kids up for the storm coming, which I bet you aren't because you'll be depressed and feel like shit. Unless you are using this time well, then you are not doing the smart thing by staying.
All you are doing is getting further into your own pit, whilst giving him time to manage things so that you are done over when he does flit.
For us, the tipping point came when he got to a stage of career where he couldn't easily be sacked. Own business etc. Lots of high profile praise, a massive ego boost, huge sense of entitlement. He basically didn't out until it couldn't harm him.
And that's him, not us. Not harming me or the kids wasn't a factor.
Yet he tells people he came out because he was so depressed he couldn't take it anymore. Total lie.