I don't live with my partner but go to his fri, sat come back Sunday night. We live in different towns due to work etc. We normally go to his mum's every Sunday but this was getting too much, so go every other week now. I knew she's not happy about it. His mum is 75 but a young 75, does voluntary work 5 mornings a week, drives etc. I met my partners sister in law other day for coffee she told me his mum was moaning saying she hardly sees him etc etc. I'm fuming, just had her round for dinner last week! Not sure what to do feel can't speak to her about it as don't want to get sis in law in trouble. Tbh feel like going less, or say partner to go but I won't. Any advice please? Thank you