your story is very sad to read, i dont understand why he led you on so far, i hope he feels the guilt for a long time,
the worst is what hes done to your children and leaving you to face them with his broken promises,
be strong , brace yourself and let go,
more important than him for you is yourself,, your children and your family, they will always be there for you,
you got lots of good advise here from all these wonderful warm friends who are always here for you,
take care, you will get through this ok