Both my mother-in-law and sister-in-law are ridiculously mean when it comes to others. They don’t hesitate to buy things for themselves, but they take advantage of everyone else’s generosity.

Whenever we go out together, they just wait for someone else to pick up the tab. On the very few occasions that either of them has offered to pay, they have forgotten or misplaced their wallet. It’s ridiculous.

One time my mother-in-law said that she’d like to buy a film ticket for me since I always pay, but after I parked the car and met her back at the entrance, she hadn’t paid and didn’t offer. Instead of confronting her, I just went and paid.

As far as I’m concerned, the monetary price isn’t worth the confrontation – but I’d just like to understand what makes them OK with this behaviour. They also offer to help out with chores but then don’t follow through.

My husband doesn’t care and happily pays for them, but they expect me to pay as well when he’s not there and it’s driving me crazy. What’s going on here? I’m getting increasingly resentful.

Sympathies. Isn’t it interesting how we have things we want to say, and yet so often we can’t communicate with the very people who could do something about it? It might be worth thinking about why you’re afraid of just bringing this up with them. It doesn’t have to be a confrontation. Often when we find we can’t say things to people it’s because we fear the relationship won’t take it, we doubt our motivation or we’re afraid of how we’ll be judged. But it’s perfectly reasonable for you to wonder why they don’t pay.

Psychotherapist Armele Philpotts (bacp.co.uk) wondered what the situation is “in terms of relative wealth”. Not that this excuses their behaviour, but it may explain it if they aren’t as well off as you and your husband, or if that’s their perception. It’s easy to always think that people do things with malicious intent, but what if there were a different reason?

Philpotts also wondered about your father-in-law, where he was and if “your mother-in-law is a widow or if your husband is trying to step into his dad’s shoes if he [father-in-law] always paid for everything. Is your husband now perhaps seen as the ‘head’ of the family?” Of course if you were able to discuss this openly, you could find out what their expectations and perceptions are, because they clearly have a narrative that makes this behaviour acceptable to them.

Philpotts also wondered if your in-laws feel pressured into turning up to things they can’t afford. “Could you perhaps suggest meeting up to do things which don’t cost anything, like a walk?” Or a picnic where you all bring your own food so if they don’t bring anything it’s more impactful on them?

I did note that you said they were also like this about helping out. And of course some people are just really selfish. Can you ask your husband for some background to help illuminate their behaviour and his: why does he always pay?

“What would happen,” mused Philpotts, “if at the cinema you said: ‘Oh you haven’t bought the tickets – you said you would’? Is there a belief that you’re not allowed to be assertive because there will be a confrontation?”

Unless you divorce, these people are in your life for the long haul, so it’s really better to bring this up now, calmly, than face a lifetime of simmering resentment and the possibility of you exploding one day.

I asked Philpotts: what if these in-laws are just selfish and cheap? “You can’t change them, but you can change your expectations,” she said. “You have a choice: you can be generous with them, but if someone is withholding money/time it’s fine to match that energy. The sad fact is, you can’t have any insight into their behaviour unless they do. On some level this works for them.”

If your husband and you always step in, there’s little need for them to change that behaviour, whatever the motivation behind it. But I’m guessing that you pay because you can’t stand the awkwardness. Could you bear the discomfort, for a bit, to see what they would do if the bill came and you didn’t pick it up? I once had a friend like this and the habit broke when I just said: “I’m not paying this time” – simple statement of fact. It took me a lot of courage, but I can still remember that feeling of release. It’s surprising how strong you can feel when you finally say how you feel.

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