#1 Have your own space. Whether it’s a new or long-term relationship, this is applicable to anyone who’s not single. You need to have your own personal time. If you live together, give yourself time to do things you like without your partner. Hang out with your friends, work out, read a book. Do things on your own without them to keep your independence.
#2 Choose your battles. If you’ve been together for a while then you’re aware of the flaws you both have. The more time you spend with someone, the more information you have to use against them in a fight which isn’t good.
Instead of picking up every argument that comes your way, take some time to think about whether or not it’s actually worth the fight.