There are no “nights off” anymore, so each of you needs to make an extra effort to take “me time” and spend time with your friends. Don't become that weird hermit couple that only hangs out with each other. Your friends will laugh about you being on lockdown behind your back.
Make a concerted effort to do your own thing on the regular. Be respectful of how she likes to spend her time, even if it’s something you don’t enjoy. If she wants to read for three hours, instead of getting upset you can’t do something together, happily use the time to pursue your own hobbies.
Leave the apartment. Give her a chance to miss you. Keep being the interesting, self-sufficient person who attracted her in the first place, and this whole living together thing will work out just fine.