Your partner's spent the whole day at the computer. They get up and wander off to the restroom, or to grab a drink, and you lean over innocently to clean up their workspace. As you're picking up the rumpled paper, and wiping away the crumbs, you notice they left their Facebook messages open. Though you tried not to peek, you saw their ex's face peering back at you from the screen. What the eff?

Unless you're already privy to the fact that your partner still talks to their ex, it can be a jarring discovery. And if you don't hear it from them, it can cause a bit of doubt surrounding the stability of your relationship. How often do we hear stories about people bumping into their ex at the supermarket and ending up on a date with them a week later? It's so cliché it's a go-to for romantic comedy.

So, you ask them about it. If that wasn't your first thought, you need to take a few steps back. Unless you read the messages, too (please tell me you didn't read the messages), and found something shady going on, you've got no reason to be upset with them. Exes contact each other all the time. Some remain good friends, even. Don't jump to conclusions; just ask.

When you ask them about it, they act a little shady. Nervous. As if you caught them at something they shouldn't be doing, or something they think you'll be upset about. Who doesn't get nervous when you put them on the spot, though, right? They say nothing happened, nothing happened. It's all good.

Until you see their Facebook again, and the messages are gone. They deleted them! What'd they do that for?

This has happened to oodles of Redditors, who responded to a plea for advice in /relationships. And if this has happened to you, there's good news! They (mostly) say there are other reasons to delete messages on Facebook, like keeping a tidy inbox, or not wanting to see the ex's face.

I can definitely empathize with not wanting to see an ex. Most of us can, I think.

But how can you tell the difference?

Even if the situation seems fishy, approach it rationally. Ask your partner why they deleted (or archived, as the case may be) the messages. Ask if there's anything you should know about that they haven't had a chance to share. Don't be accusatory. Do explain why you feel uncomfortable.

Give them a chance to respond, and pay attention to what they say. If they're telling the truth, while they may still be nervous, they'll most likely have their answers straight, and give them with confidence. If they're not, they may fish for the response that will appease you, or try to only tell you what they feel you need to know.

If you're not satisfied with their answers, examine why you feel that way. Is it possible you're just grasping at straws, or do you think there might be something to your worries? In the end, only you can decide what to believe and act accordingly.

But chances are? They just didn't want to look at their ex's face every time they logged in and checked their messages. And really, who can blame them there?