I've read several stories where Buffy talks casually about hitting Spike or breaking his nose even after she admitted to loving him like "he just saved himself from a broken nose" I'm looking for fics where Spike defends himself or even fights back and does not let Buffy walk all over him

There's only one fic I can think of that fits your criteria:

Payback by dreamweaver
Summary: On his way back to Dru after 'Lover's Walk', Spike suddenly finds himself transported to his crypt the night after 'Smashed'. Horrified that he, a master vamp, should have been tamed and furious at how he's been treated, he blames Buffy for everything and is determined to pay her back in spades.

It's not after she admits she loves him, but Spike definitely has her and the Scoobies' numbers in it and basically drags Buffy out of her "I was torn out of Heaven" depression with some very tough love.

I hope somebody else might post some more because I'd like to read some like that as well.