These days, being single doesn’t mean you’re entirely unattached. If you’re not in a committed relationship, you are probably talking to multiple romantic interests. Or maybe you’ve been burned by someone who was.

With the abundance of ways to meet people, including dating apps and social media, friends, work, or mixers, it’s hard to figure out the rules of engagement when you’re dating around or seeing someone who might be. The blurred boundaries of modern dating often lead to misunderstandings and hurt feelings.

Jonah Feingold, a 29-year-old man in New York, says he’s been less than clear with people he’s dated, and it’s led to mismatched expectations. He’s since changed his ways, he says. “This was old me — me before I knew how to communicate my feelings in a mature way, and in a way that would benefit myself and the person I was dating,” he says.

So, what are the unwritten rules of dating without exclusivity? Early on, it’s important to keep other flirtations under wraps. If you and a new partner have friends or connections in common, you’ll need to be extra careful not to parade dates in front of each other, says Lindsey Metselaar, dating expert and host of the millennial dating podcast “We Met At Acme.” “If you run into that person out at a bar, club or other function, it is beyond disrespectful to make out with someone else or leave with someone else in front of them,” she said. “It’s also disrespectful to be posting on Instagram with the other people you are dating, even if it is ‘storying,’ or commenting racy things on others’ photos.” Remember, online activity is often visible to all your dating connections.

Mum’s the word, agrees Andrea Syrtash, a relationship expert and author of “He’s Just Not Your Type (And That’s a Good Thing).” “Don’t talk about your interest in someone else, or how fun it was to hook up with someone else, just because you’re not yet exclusive,” she says. “There’s a way to convey that you’re dating others — you’re not 100 percent available, all the time — that will let the person you’re dating sense that it may not be a relationship yet.”

You don’t have to make it official immediately. But there are still ways to show that you’re interested. Feingold says he likes to clearly and verbally end a good date by saying: “I like you; I’d like to see you again.” Such a statement “lets them know my intention, it hopefully allows them to say theirs, and means we don’t need to play the game of, ‘Do they like me?’ ”

Even if there’s clear interest, two people might have different romantic goals. Mention those goals when it feels right, or when you need to make your expectations clear. People often make assumptions about the exclusivity of the relationship that their dates may or may not share. “Every person has their own experience-based understanding of what exclusivity means and when exclusivity occurs,” says Laurel House, a celebrity dating coach and host of “Man Whisperer Podcast.” “Some people assume that if you go on one good date, you are now not dating anyone else. Others continue dating multiple people for months or even years. Some assume that exclusivity comes before sex, and some after.”

Such assumptions can lead to hurt feelings. Two people might continue to date others, even if they want to be exclusive, House says, because both wonder if it’s too soon to have the conversation or if the other person feels the same. This breeds “distrust, jealousy, insecurity or competition,” House says, which can doom the relationship before it begins.

Tom Ella, a 29-year-old single man in Queens, thinks “it’s incumbent on whichever person wants the relationship to change to bring it up first,” he says, whether that’s wanting a label or simply wanting to spend more time together.

There are a couple exceptions, though. If you have a personal boundary, such as no sex before exclusivity, Metselaar says, you have to be clear about your limits. And if you are the one pursuing the other person, state your terms early on, particularly if you’re unsure what you want or just want to have fun. “The responsibility [to draw lines] lies in the person who initially pursued the relationship in the first place to be upfront,” Metselaar says. Coming on strong, only to disappear post-hookup, is not a good look.

Ella has determined a few to live by. He avoids seeing more than one romantic interest on the same day. “You don’t need to volunteer that you’re seeing other people if you don’t want to,” he says, “but especially if asked, be honest.”

The best-case scenario is knowing what you want before you get involved with someone. “There are three dating purposes, and you need to have personal clarity as to what your purpose is,” House says. “First is fun, which is emotionally unattached and just having a good time. Second is exploration, which is exploring yourself or the world through others and learning about your interests by having different experiences. And third is commitment, which means you are ready for something real.”

Having a purpose to communicate to others reduces the likelihood someone will get hurt, House says. “You’re being disrespectful if you are not being honest about what you are feeling,” she says. “Don’t lie to yourself, to them or both, and don’t avoid the conversation for fear of what they might think, feel or say,” House adds.

And definitely don’t act like you’re looking for something serious if you’re not sure that’s what you want. Angela Commisso, 31, in Ontario, Canada, was seeing a guy where all signs pointed toward exclusivity. He talked about wanting to meet Commisso’s family, brought her thoughtful gifts such as homemade food and claimed he’d never met anyone he could see himself with like he did her. “He invited me to a weekend trip; the connection was unreal. Everything was going in the right direction,” she says. “But on our trip, I sort of asked him about us and he said he wasn’t ‘in the space to commit.’ I told him he couldn’t have his cake and eat it, too; he said he was under the impression it was ‘light’ and ‘just friends.’ ” But that’s not at all what his actions were conveying.

Some actions tend to show you’re invested, so make sure you’re not sending the wrong signals. Don’t text all day, every day. Don’t ask them to meet your parents or friends. Don’t stay over at each other’s places most nights. Don’t go on intimate getaways. “These are definitely no-nos, but it happens all the time,” Metselaar says. A lot of these “serious steps” can happen as people are “trying you out” to see how you fit in with their lives, including meeting friends or traveling together, Metselaar says.

Once you’ve introduced the person you’re dating to friends and family, spend multiple days a week together, talk about the future, and are sexually intimate, “it would not be unreasonable for the other person to assume you’re in a relationship or heading into one,” Syrtash says.

If you’re not sure you’re ready for exclusivity, be upfront about that before you ask them to go away with you, meet your parents or become your all-day text buddy. “It is worth sharing your situation,” Syrtash says. “Something like, ‘I love hanging out and now that we’re intimate, I feel like I should tell you that I’m still seeing others. I don’t want to be presumptuous since maybe you are, too.’ ”

If you don’t want the person you’re seeing to hook up with others, you have to draw some clear boundaries, Syrtash says. Lydia Kociuba, a 41-year-old woman in Rochester, N.Y., says her policy is to always be transparent. She met a man who lived six hours away who came to visit, and after they got close quickly, she had to say something. “I couldn’t keep continuing that knowing that I wasn’t confident it would go anywhere. All I could do was be straight and let him know that I wasn’t in the same place as him,” Kociuba says. They ended on mature, understanding terms, she says.

The goal of dating should always be to spend time with someone on mutually agreeable terms. If one person wants a no-strings-attached fling, and the other wants something serious — but neither communicates it — there’s only one ending in store: a messy one.