Ok, so (as a bit of background) my DH's brother and his wife are nice enough people, very well-off - they are much more materialistic and put a lot more stock in appearances than us, but it takes all sorts. I only raise that as it's relevant!
Both work full time and earn a very substantial wage (over £250k pa in total). We are full and part-time respectively and earn less than half of that, with more outgoings.
They have been together for about 13 years and every year we have bought them both Christmas presents and birthday presents. (DH buys for his brother and since I do everyone else's presents, I buy for her). I know from previous things she's said and the reactions she's had to other gifts that her standards are high and she expects 'decent' presents (her words). I've spent probably £30-50 on her birthday present each year (trying to utilise the last minute sales as her birthday is right after Christmas!)
In all those years, they've bought me two presents for my birthday (a few days after hers). One was a bead necklace, which was nice (but I suspect regifted as it wasn't my style) and the other was a Superdrug smelly set which I know cost £4.99 because my colleague bought the same one for a random person she drew in secret Santa.
Every other year I've not even received a card or a text or a Facebook message. So I felt like a mug and told my DH (who was in complete agreement) that I wasn't buying her birthday gifts anymore. Fine.
Except last time was her 40th and afterwards my MIL kept asking 'when will you be giving SIL her present? It IS her 40th...' I've been hearing about it non-stop (though I should be clear, I received nothing from them for MY 40th) and I'm wondering - am I just being petty? I don't like the idea that 'we only give to receive' but I also don't want to feel like an unappreciated doormat...