My SIL and I have a friendly relationship generally.
We have our issues on some level as I think we are quite different.
However I've always involved her / invited her out etc and she's always come over to our house to play with the kids etc. she's younger and childless / unmarried.
A few months ago I noticed that it's always me, asking her to do stuff / suggesting things etc. as well as checking in on her to see how she is etc.
I hadn't really noticed before, but she wasn't really making much effort herself to suggest meet ups etc. perhaps she did in the past and then stopped, I think that could also be a factor. But since I realised I completely pulled back and only see her at family functions.
I still act the same etc but just don't make any extra effort anymore and neither does she.
I can be a bit black and white about these things, but obviously if someone is not making an effort- then it's OK for you to step back and wait to see if they actually want to see you and aren't just hanging out because they feel obliged to ?
She's my DH's sister.
I can't help but think that she may ask herself why I've stopped initiating stuff or if she's just glad I don't anymore.