I would agree that a sit down is appropriate and even necessary especially at this point. Though when this has happened in the past it ended up that I am remarried and daughter doesn't want my wife involved in anything. (which I disagree as to being appropriate) My own mothers position on everything is that my wife and I should get over the fact that my ex wife is included in family events and we disagree that we should have to feel uncomfortable and even unwelcome so that my ex can participate as well. Anyone else I have fully described things too has said it is wrong of my mother to continue to 'force' my ex upon me and my new family.
Is this a part of the rift between my daughter and I? Yeah I could see the issue between my mother and I as becoming part of the issue since by me/us asking to exclude daughters mother if including me that she may interpret that we didn't want daughter there however, to be fair the request was made that when we had daughter it was us and when ex had daughter it was her so that daughter could participate either way but that wasn't acceptable to my mom (grandma from now on) and she continued to invite and make a point that we knew ex was invited even if she didn't have daughter. As I know the only person who someone can change is themselves my wife and I decided that it was best to just not attend any events they held and even had several occurrences where we then held events that ended up in more fights and arguments with grandma as the only way to think is grandmas unless you wanted a fight. We were told that since grandma was invited to grand sons birthday party and other life events for the grand children where she had to associate with her ex it was no different that she was including mine so to get over it. So much drama it just is best to keep grandma as far out of the picture as possible in our opinion, it doesn't stop us from trying to give recognition to her when appropriate. We just don't go to the events or grandmas house for visits.