Husbands and their mothers.

How often does your husband/SO talk to his mom? 

I am asking because my husband has never been super close to his mom, but for the past year they have started talking twice a week on the phone. I just think it is a little much. 

Am I overreacting about this? I would be fine with once a week, but having set days to call her is making me feel jealous. I've tried talking to him about it and he doesn't think it's an issue and that I am only acting like this because of pregnancy hormones.