Barbara,

   If she is any kind of woman at all, she will never, EVER put your son in that position. While my MIL and I don't get along, I would never, EVER put my husband in the position to have to make a choice between his mother and myself...that just isn't fair to do to him. My husband and I have had that conversation and I ALWAYS tell him that while I may not like his mother, I would never, EVER ask him to not see her or have a relationship with her. I have asked that he try to understand my position and to let me stay home when he wants to visit or do holidays with her. She may be a certified nut job but she is still his mother and I would never put him in the position to have to pick one over the other. That just isn't fair and when you love people, you don't put them in that position. You just don't.
   I think you have the right attitude and things will work out just fine. Slow and steady...she's going to be family and hopefully they will be married for a very long time....so you have a long time to work things out...no need to rush or force the relationship....it will happen if you let it. :)

Michelle