LW1:  If you won't talk to her/them about it, nothing is going to change.  If you have truly done nothing, then it's on her, for whatever reason.  Maybe she doesn't like mother types because her mother mistreated her, or maybe HER mother forces her to make a choice between the two of you.  Maybe she feels that it's you or her where her husband is concerned.  Who knows?  Unless you ask, you'll never know.  I would not speak to your son about it, because that could make things worse.  If she finds out that the two of you have been talking about her, she'll get really mad.