Sex with the ex.

That’s what a lot of singles will be doing over the holidays. Indeed, a survey of 2,000 singles by dating site Plenty of Fish found that roughly one in three admit that they’ve hooked up with an ex over the holiday season.

And that’s not the only person they’re getting it on with. About half of people polled admit they’ve previously kissed a coworker at an office holiday party, according to a 2015 survey of 2,000 people.

Also see: Charlie Rose and Harvey Weinstein just killed the office Christmas party

Both these hookup types can be questionable. Dr. Crystal Lee, a licensed psychologist and owner of LA Concierge Psychologist, notes that they can lead to “confusing feelings towards your ex and awkward encounters with your co-worker.” For some people, the feelings caused by these hookups can mean pricey trips to the shrink — at roughly $75 to $150 per hour — to analyze the “why” of it. For others, it can mean a new job search so you don’t have to deal with the coworker hookup fallout.

Most of us, of course, know hooking up with an ex or co-worker is often a questionable choice, and yet we do it anyway. The reason: We’re lonely.

“During the holidays, there’s an increase in feelings of loneliness and isolation. Some people hook up with others in order to fend off those feelings,” explains Lee. What’s more, all those holiday festivities can sometimes make being single feel even more lonely.

“Singles go to parties, family and social events, and glance around the room and describe feeling as if they are the oddball without a pair on Noah’s Ark,” says Dr. Fran Walfish, a Beverly Hills family and relationship psychotherapist, and the co-star of “Sex Box” on WE tv. “The hookups can be explained by loneliness and the wish to snuggle up next to a warm body and be held in someone’s arms.”

All that bubbly doesn’t help either: “There’s generally an increase in alcohol consumption (think of all the holiday parties that happen in a short span of time!) during the holidays, which can lead to more hookups because of decreased inhibition,” says Lee.

Worried that you might make a questionable hookup choice this holiday season? The first step is to combat your feelings of loneliness quickly. “The antidote to loneliness is activity. Loneliness is kicked in the butt when the person takes action doing anything. Whether it’s washing dishes, organizing papers and doing housework, making a phone call to a friend, meeting someone for dinner, or joining your neighbor’s weekly poker group,” Walfish says.