My MIL and SIL have a habit of taking our stuff and I wanted to get some perspective on it as it keeps happening.
If we lend them something they won’t return it and get very defensive if I see the item in their house and say ‘oh do you mind if I take that back I need it.’ If we ever leave something at their house by accident after we’ve visited they similarly won’t return the item without a lot of tension. I’ve asked my partner about it and he’s said maybe they see the item as theirs if it’s been left long enough. But this is only a matter of hours / days, weeks at most. I don’t understand it. The items are rarely expensive but things that we need and have a personal attachment to, including things for our baby. On other occasions it’s been more blatant where they’ve taken things of ours from our house ‘by accident’. I say it this way as it’s always the same things - for example my SIL takes the same two throws which end up back at their house being used in her bedroom. She’s taken them again for at least the third time.
My partner said that she had a problem with stealing as a child and would often take things from friends houses, including a hamster one time!
I’d appreciate any advice to address this or at least understand the psychology behind it.