ESH. Why do you care if his toenails are too long? That shouldn't affect you. He showers daily, so unless he's doing something very wrong, he's got to be clean.

On the other hand, it's considerate to take your partner's preferences into account re: pubes and teeth brushing if you want them to go down on you or kiss you, so he could try a little harder there.

If his breath is that bad without obvious cause (e.g., just ate something garlicky), has he seen a dentist or doctor?

You also say you've bickered about his hair and wardrobe. You can't expect people to change, and that just sounds miserable all around.

This is hard to hear, and I know I wouldn't have wanted to consider this at 23, but if you started dating at 19, you're both still figuring out who you are and changing as people, so you will run into compatibility issues more often than not. You can stay with him, get used to these things, and be really willing to compromise, or walk away if you've grown too far apart and take what you've learned into account when looking for your next partner.

It might be worth having a conversation about whether he wants to change and just needs some encouragement and patience. Also, he should feel comfortable asking you to brush your teeth if it bothers him.