Thank you very much to everyone for their feedback.
I don't speak to them on the phone because they don't call me and when I call my son says "I'll call you back in 20 minutes and doesn't".......
It's curious to me that they are being oh so hostile BEFORE their wedding. I never thought I would think this but attending the wedding is not high on my priority list, especially since the bride deliberately schedule the date to coincide with a big charity event that I work for every year......."oh, I thought it was around then......." was her subtly hostile reply when I found out the date.
At this point in time, I will deal with them via email........maybe once every 2 months, that's 6 times a year, and send emails to them for birthdays, Christmas and make a donation to a charity. Last year when it was my birthday, no phone call, no email, no nothing. On Mother's Days, no card, no flowers, but my son did make a phone call late in the day to wish me Happy Mother's Day.
Now that my son is into his 30's, I expect more. His GF has a habit of calling him constantly if he is with me alone (like once every 3 years). One year on Mother's Day, he came to my apartment which was across the city to wish me Mother's Day (no card, etc.) and she phone him 23 times in the 30 minutes he was with me.
I'm not going to worry about the whole "be nice to us or you won't see your grandchildren"........that game works both ways, "Be polite and courteous to me or their grandmother may be on the other side of the globe, helping out other people's children in a refugee camp".
I think these DILs live for the fight, so they can prove to the MILs that they are the "Boss"......I can't get an enduring portrait of her dressed as Hitler in a little mustache and a "Sieg Heil" salute out of my mind.
She is who she is, and since her parents have spoiled her and catered to her every whim, she's expecting me to do the same. I have done my best for 5 years, buying gifts, dinners, etc., etc. but no longer. My son was not brought up that way (I brought him up on my own) and while there were many times when he was growing up that I was so proud of him that I thought my heart would burst out of my chest, this is definitely not one of them....I have to say that I've been overwhelmingly sad in the last 2 months, it's like a death in the family, and it is, the death of my son as the person who I thought he was and I now I have to deal with the reality that who he has become, under the thumb of "she who must be obeyed" and too passive to stand up to treat his mother with basic courtesy is not a pretty picture. While there were many things about my ex-husband that I didn't like, he never would have tolerated me being bold and demanding with his mother, and I wouldn't have considered it let alone followed through on it, MY mother would have had a fit.
This future DIL is looking for the squabble, so she can get her jollies. She won't get it from me. The only thing she will get from me is distance, geographical and otherwise and the bare minimum of courtesy. I'm not going to sit down with them and try to be honest. There's no point, her constant plague of phone calls is indicative of someone with "stalker" type tendencies and being honest with those people is always a big mistake. Knowledge is power and I won't give her any more knowledge other than the fact that I am still on the planet, which I will make sure she gets every 60 days.
I have decided that since I live some distance away from them, I won't make to effort to drive to see them, stay with them or have/buy meals for/with them. They have never come to visit me, despite my many invitations. I will deal with them via email alone, and likely will decide to attend the wedding......but will hire a big, ugly, burly motor cycle gang type actor dude as my escort. I'm not looking forward to spending a minute with my ex-husband now that his long term relationship has ended, with the whole emotional "Oh don't they look lovely together"......so me and "Tiny" can arrive, stay as long as necessary for the ceremony, photos, speeches and then skeedadle on the back of his Harley. He can count his earnings for the wedding gig and then I will go to a lovely hotel for a massage and spa treatment followed by a quiet evening in the company of a couple of wonderful friends.
It's very sad, disappointing and not the way I had expected that things would work out. As my aunt said to me "I'm sorry to have to say this to you, but "That's life".