There are a million little facets of roommate etiquette–when you’re sharing a living space with someone, it’s important to be cognizant of things like cleanliness, noise, cultural or religious sensitivity, and moderation (translation: you shouldn’t leave food-encrusted dishes in the sink for weeks, have rowdy parties on Monday nights, tell rude jokes or hunker down in front of the TV at 6PM each day). One of the most sensitive situations is that of your roommate’s boyfriend or girlfriend. If you or your roommate is in a long-term relationship, there is certain etiquette that should be followed to ensure that three doesn’t become a crowd.

Common Mishaps

Although it probably feels like the world is out to get you when you and your roommate begin having relationship issues, this phenomenon is actually quite common. As you open the table to talking about relationship “rules,” keep these common roommate problems in mind:

  • One roommate’s significant other stays in the apartment too often

  • A significant other and a roommate do not get along

  • The significant other uses common spaces–like the living room, kitchen and bathroom–to the detriment of roommates’ schedules

  • The roommate’s boyfriend or girlfriend incurs utility expenses (i.e. takes too many hot showers) that he or she never pays for

  • If more than one of the roommates has a significant other, battles arise between who gets to stay at the apartment on various nights

Be Open

First of all, be open about your relationships, and ask your roommate to do the same. If your roommate’s girlfriend or boyfriend is already becoming a problem early on in the lease period, sit down and have a chat. Even if you and your roomie are both currently single, there’s always the chance that a relationship will develop–so it’s good to be open and honest before an issue is even on the horizon.

Set Rules

After you’ve set the stage for discussion, create a list of rules. If your roomie thinks this sounds absurd, assure him or her that it’s for the best–after all, your roomie could end up in a similar situation if and when you find your next main squeeze! Consider all possible arguments and have a plan in place in case they arise: For example, determine that if your roommate’s girlfriend begins staying over more than three nights a week (shower and bathroom time included), she begins chipping in on utility bills.

Don’t Forget About the Positives

It’s important to remember that your roommate’s having found a loving partner is really a good thing. If this person is staying over in your apartment night after night, your roommate is probably pretty happy with the situation. It’s important to put this into perspective: Even if you don’t get along with your roomie’s partner, you should be happy that your friend has found a special person. Don’t forget: Your friends’ significant others can become your own lifelong friends! With some reasonable boundaries and a good attitude, you can turn a potentially disagreeable situation into an opportunity for happiness and friendship.