Sorry might be a long one..
Dh's family run a business based from their family home. FIL and BIL work in the business. My MIL is a matriarch type figure and looks after them though plays no part in the business. FIL and BIL come in twice per day for drinks and lunch.
Historically I have always gone over every Thursday when they come in for a drink and would often stay for lunch. My fil would often take one of the children out to work with him (lorries etc so quite exciting for them).
Recently mil and I have started looking after my 12m old nephew on a Thursday. We share the day but it means I no longer get to go up for a drink (although i will have lunch there whilst looking after the children) and the 2 dc who are not at school don't get to go out with their grandad.
I get on very well with my mil but she has a lot of responsibilities and I know she finds it hard if people are always turning up at the house so I limit the times we are there. My SIL works 3 days per week and has started to go and visit at drinks time on one of the days she is not working. I now don't feel like we can't visit in the week as it is too much for my MIL. I feel like we are missing out on our time with my inlaws. I also feel like my SIL should be a bit more aware of this and should realise that if she goes it means I can't. I am starting to resent it a bit especially as it is v hard work for me looking after my DN (I have my own baby and toddler as well as 2 older children) and what was the only time in the week I had support from family is now taken up looking after him. I wouldn't mind going on alternate weeks or something but I feel awkward mentioning it and also feel I shouldn't really have to as to me it is fairly obvious.
So AIBU?