Most of us just accept that relationships mellow out over time. The intensity isn’t the same, the butterflies are gone, and you’ve found yourself describing your relationship as “comfortable.” Fine. Normal. Expected, even.

But there’s a difference between a relationship that’s settled and one that’s flatlined, and a lot of couples can’t tell which one they’re in.

Enter parallel life syndrome. It’s exactly what it sounds like: two people in a relationship who aren’t really in a relationship anymore. You exist side by side, same house, same bed, same Netflix queue, but your lives stopped intersecting a while ago. Different schedules, separate friend groups, and whatever “together time” you do have involves two phones and zero actual conversation.

“Just because you have the time together doesn’t mean that’s quality time,” New York City-based dating coach Erika Ettin told SELF. “And just because you’re still in a marriage doesn’t mean it’s automatically progressing.”

3 Signs Parallel Life Syndrome Has Entered the Chat

So how do you know if you’re just in a comfortable groove or something that’s starting to lose its spark? A few signs worth paying attention to:

• You make decisions alone, then loop your partner in after the fact. Booked a trip. Bought furniture. Signed up for a half marathon. Oh, and your partner found out about it later. According to couples therapist Patrice Le Goy, PhD, LMFT, losing that instinct to include your person first is one of the earliest warning signs.
• The small stuff has gone missing. Not talking about sex. Talking about the hello kiss, the random “thinking of you” text, the hand-holding on a Sunday walk. “Little points of bonding chemically make us feel closer to each other,” Ettin says. When those start feeling like effort, something has already shifted.
• You keep putting romance on the back burner because nothing is technically “wrong.” The vacation can wait. Date night can happen later. The logic makes sense until later never comes, and you’ve both gotten very good at meeting your own needs without each other.

That’s what makes parallel life syndrome so insidious. No blowout fights, no obvious red flags. Just two people slowly becoming very efficient roommates.

The fix, according to the experts, comes down to one thing: consistency over grand gestures. Ask about their day and actually listen. Pick up their favorite snack. Take turns planning something that doesn’t involve a screen. “You have to tend to a marriage just like you would a garden,” Ettin said, “with consistent intention and care.”

Not exactly revolutionary advice. But it works. The gap between a relationship that feels alive and one that feels empty usually comes down to intention, not circumstance.