Unwritten rules of marriage!

It was my in laws wedding anniversary yesterday, I forgot to take their cards when we went for tea on Sunday and I forgot Monday.

So instead I had to traipse into Nottingham yesterday with the children and drop the cards off.

But since when is this my responsibility? Is there some unwritten law or nuptial I missed that this becomes your responsibility when you get married or become a girlfriend?

Why on earth do I have to remember to buy the cards, sign and ensure they get to them?

I'm pretty sure it didn't matter if they got one before I came along in fact it was a family joke about my husband making a card once and he would never be expected to remember my parents anniversary let alone buy a card!

So does anyone know why all of a sudden you take on this responsibility and would I be frowned upon for not getting them the cards or would my husband get the blame?!?

One of marriages many mysteries eh, rant over and I bid you a good day ;)