I just have to say... what kind of man gets engaged to OW when he's still married?
The kind that has no conscience, is selfish to the max, has no sense of ownership or responsibility in the matter, and wants what he wants no matter what the cost is to his family. Destroy a family, a home, lives that he's supposed to care about. The kind that is a sorry piece of sh!t.
Sorry.
But you deserve better than to be treated the way you have been...lies, deceit, etc.. What you need is a massive dose of self-love and self-respect, especially under the circumstances. You are a good woman and a good mother.
"Always go straight forward, and if you meet the devil, cut him in two and go between the pieces." - William Sturgis, clipper ship captain, 1830's.