Moose
I can completely understand your position. I also have a grandson (5 yrs old) and my AS and his exgirlfriend are not together. It has been a struggle to maintain neutrality but I have managed to do it and, as a result, I get to see my sweet grandson frequently.
I have never hid from my son the times that I have spent with my grandson. His exgf has not filed any charges against him, nor has he given her any reason to, so I don't have that issue to deal with. However, I do deal with my AS making very derrogatory comments about exgf and he constangly whines about how he doesn't get to see his son. To which I reply: "Son, I am not responsible for your relationship with exgf. I elect to stay on good terms with her so that I can spend time with my grandson. How you choose to handle your relationship is your business.....and what I choose to do is my business. Conversation over."
The really sad part of all of this (which is why I have absolutely NO sympathy for my AS) is that he generally always knows when his son is here with me and he often makes NO effort to come spend time with him. That is why his whinning has no affect on me. I just keep telling myself that I am not responsible for my AS's relationship with his exgf or his own son. It makes me sad.......but it is one more thing that I have no control over.
So enjoy the time you get to spend with your sweet grandchild and let the father rave on. My husband has a saying "Rave on cat poop.....someone will cover you up." It always makes me laugh.
gentle hugs