My lesbian ex-spouse came out about 4 years ago and left our son (who was 16 when she left and 20 now and lives with me) and I pretty much alone (aside from divorce issues)  except for a few small patches of time where she and our son met for a few times and then things went cold between them again.   Our divorce was finalized this past June and my ex immediately announced that she was getting married to a woman she had been seeing for a year and a half.    All of a sudden the push is on by her to re establish a motherly relationship for our son and have him get together frequently with her and her live in partner.    My son wants to have some relationship with her and not adverse to meeting with her partner (it's just another person to have dinner with). 

I have extreme problems with this thawing of his relationship with his mother and the thrusting of her new partner into his life (and indirectly my life).     My ex-wife created great emotional and financial problems for him and I by her leaving the house and family,    We had a horrific divorce which caused my son great stress as he feared us having to sell the house (we didn't).    This turn of events has caused me great stress and to be honest I am not comfortable with him being around his mother and her partner because I don't approve of gay relationships (nor does he) and because I feel this woman while not the actual woman my ex-wife left me for she represents what my ex was looking for when she left and the life she wanted.   Also I have taken care of my son through several problems some of which my ex-wife's leaving caused over the last 4 years.  She won't even admit her actions caused the problems.      

I have no problem him visiting and being with his mother.    I do have a problem with being with her partner.  I feel like I was removed from the family and replaced with this woman.   This issue is retriggering the anger and feeling of betrayal I felt when my ex-wife came out and left.   How do I deal with this?