Retroactive family charge
There is a distinction between a gift and a debt. A gift produces an asymmetry. A genuine gift produces an asymmetry; you can’t immediately ‘give back’ or repay, and that’s part of what makes it genuine. It’s not something you’re expected to pay for.
This father, although, inverted that mechanism by retroactively saying: ‘You owe me’. Many times, although it misses the point of gifting, a gift comes with a subterranean sense of debt; the thing is, that it shouldn’t be explicit, otherwise it becomes a quid pro quo, a simple economic exchange.
The important thing here is the surprise. That is what makes it fishy. If he had told his son and daughter-in-law they were going to pay for the whole thing, they could’ve just declined. And of course it wasn’t an accident. We’re talking about adults who know their way around money.
This retroactive charge sounds more like an unelaborated emotional charge coming in the form of a financial one than simple miscommunication. The father’s attitude, apart from being very immature, is very inconsiderate of the obviously different financial situation of his daughter-in-law.
It is a really poor way to maintain authority; the father gets to determine what counts as generosity and what doesn’t, and you have no say in what you want to participate in. You were forced into that economic agreement.
You are not included; you are paying for a service I provided. This type of generosity is persecutory; it creates a demand, and anyone should try to escape deals like this. But this deal wasn’t even disclosed from the start. I really think it is the boyfriend’s responsibility to talk about it with his father and leave his girlfriend out of it; after all, he is the one who has issues with his authority.