Sounds like your doing great! Going out, hitting the gym, dinner, keep it up. Life just keeps pushing up daisies as the days go by.
Hey, my suggestion for the S and W calling, is just dial the number and hand him the phone. If she chooses not to answer, her problem, and you tried. Once he is done, I wouldn't talk to her, just hang it up, say something like, "Tell Mom you love her, and say goodbye." Then hang it up.
If she needs to talk business with ya she will call back, if she doesn't then your being the bigger person. Let her deal with her problems.
Just_me may have a better option. I'm not really in the best place on offering advice right now, really sick of enabling the WAS's. Think I did a lot of that.