Trusting, First, be kind to yourself. Of course it is painful. My X told me he was engaged and OW was posting pics of herself in wedding dresses. It hurt, yes.
A lot of time has gone by now. I think I would still feel somewhat sad if he said he was engaged to New Woman, but at least it wouldn't be OW.
But I guess I wonder what you hope to accomplish by saying this. I just felt that if I said something to X about engagement, I would be nothing but disappointed and hurt again, and if he is loo-loo enough to get engaged, chances are he would just rebuff you again.
Trusting, you always have come off as a good-hearted person and you have always been a friendly voice on this board. Your situation is tough. Personally, I would advise you against saying anything to him. He doesn't sound as if he is ready to hear it.
M: 16 years Bomb 4/07 OW 20s long gone Divorced 11/09 I remarried New Guy Cooperative r w/X regarding D