it's totally NORMAL to want your son's MOTHER to be his mother. and the "expect" that just seeing his sweet face would melt all the "evil" away and snap her out of it.
and yet she can't be bothered. there is something damaged inside of her.
now that the big MOM event is passed, you can lower expectations, limit visitation, and not let the kid get set up for disappointment. and that means to protect him from her.
which totally blows, but it is what it is.
you're a great dad.