Against probably my better judgment and that of pretty much everyone, I've agreed to buy two car seats for their daddy's car. I took our existing ones, along with their beds and pretty much everything else, when we moved.
And while I'm the custodial parent and I see no problem with this, he doesn't like it. I get that. He bought them brand-new, nice beds. At first I was like, "Fine, you bought beds. I'll buy new seats." But I have to buy them new beds soon, too.
So really, there's no reason I should have to buy him new car seats. Especially since I'm OCD and get the expensive Br*tax ones. It's going to cost me $400 - and they're on sale!
But, sometimes isn't it better to create good will with your actions than to "be right" about what's fair or not?