I'm amazed at how few people know about, or get, this.
In the UK, if you're married or in a civil partnership, you can (again, it was removed years ago, then quietly re-introduced) a reduction in your income tax. Why you should pay less just because you're married, I don't know. Frankly we all should pay less, but there you go.
Married? In a Civil Partnership? Apply
It takes minutes. The lower earner applies, and the higher earner gets the reduction. It's only a few quid less on my tax (a bit over a tenner or so I think) but hey, it's a tenner!
All the best!