Some rules for being successful friends with benefits (FWB)

If you've ever had a friends-with-benefits (FWB) relationship, you know that things can get complicated — you might not agree about how to approach safe sex, whether or not to sleep over, and one of you might catch feelings.

That's why it can help to set some ground rules. Having regular conversations about what you each expect from the relationship and setting clear boundaries can help your FWB relationship go more smoothly and help you avoid heartache.

 Decide on your expectations before starting the relationship

Although it's a common phrase, there are a few different definitions of friends-with-benefits, says Zhana Vrangalova, a professor of human sexuality at NYU and author of Open Smarter, a course exploring non-monogamy.

Some relationships are labeled as "just sex FWBs" which means you don't expect emotional intimacy and you have a mostly sexual and physical relationship, says Lisa van Raalte, a professor at Sam Houston State University who specializes in communication within relationships.

Other relationships are labeled as "true friends", which means you can be close friends who care about each other emotionally and have a sexual relationship, but don't want to label the relationship as official or exclusive, van Raalte says.

"Not everyone has the same goals. By knowing what you want out of the relationship at the beginning, you can communicate that to your FWB partner," van Raalte says.

Set clear boundaries

To make a FWB relationship work, you'll need to discuss what you're each comfortable with. Setting boundaries is an important way to establish trust and a feeling of safety for both partners.

There are several key questions you can discuss with your partner to help set boundaries, Vrangalova says.

How often are we going to see each other?

Will we sleep over with each other?

What are we going to do when we see each other? Will we only hook up or do other friend activities?

Will we tell other people about the relationship?

How will we act when we hang out with a group of friends?

Will we see other people?

Will we use condoms with each other? What about with other people?

 Having a transparent discussion early on gives you and your partner the chance to decide if the relationship will work out, van Raalte says.

 Be honest if you develop feelings

"We like to assume that everybody knows what an FWB situation entails and that because it isn't a 'real' relationship, we can keep emotions out of it," Henry says.

Unfortunately, this isn't always how things work out. "Even if you didn't initially want to catch feelings or develop something more, it can happen — feelings have a mind of their own," Vrangalova says.

Some common signs that you may be catching feelings include:

Making future plans together

Wanting more of their time

Feeling more emotionally vulnerable around them

Wanting to talk to them more often

One key sign that your feelings are more serious is if your partner can strongly affect your moods. "If they are responding to your messages and making plans, you're in seventh heaven," but you get depressed "if they're being inconsistent or flaky and canceling plans," Vrangalova says.

There are also a few telltale signs that your FWB partner could be catching feelings, Henry says.

They text you more often

They linger after hookups

Try to involve you in their daily life

They ask your opinion on big decisions

They rely on you for emotional support

If you think you or your FWB partner are developing feelings, it's always best to have an honest conversation about your intentions, van Raalte says.

 Practice safe sex

Don't assume that your FWB relationship is sexually exclusive — "it's important to discuss whether you're going to have other partners," Vrangalova says.

In a lot of FWB relationships, both partners agree that they can have sex with other people. But when more sex partners are involved, this can open you up to a greater risk for sexually transmitted diseases (STDs).

It's important to discuss sexual health practices —  Vrangalova says that some possible protocols include:

Using condoms with each other and with any other sex partners

Being 'fluid-bonded' — meaning you use condoms with any outside partners, but not with each other

If you decide to stop using condoms with a FWB, it's important to get tested for STDs first