I LOVE my MIL, we are so close!
It depends on if I understand where she is coming from or not, regarding the spending more time with the family than you. Reason being, when I first started dating Hubby, I was upset to hear that his mom expected Hubby to be at her house EVERY Christmas, and miss out on my family Christmas. It is STILL hard, but I have come to sorts with realizing that it is okay that she expects it. That is because she lives 1000+ miles away, and she gets to see Hubby maybe twice a year, if that. The one time that she does get to see him is Christmas, and she pays for the plane tickets for us to come there (she only pays for mine now that we are married).
Anyway, the point I'm trying to make is, if they live far apart, and they only get to see each other a few times a year, then I can understand. If they live close, and she is expecting that, that is a whole different story!
I just hope that things work out for you. . .sometimes it is hard when new families come into your life and they aren't the most cooperative. I have learned to just get along with all of mine, because it makes my life AND hubby's life a lot easier.
On that note. . . I LOVE all my in-laws now. . .and couldn't be happier with the in-laws I got "stuck with." haha