I'm lucky to have a gamer wife who games on her own as well, so playing games together is never a chore or "bringing her into my hobby." It ends up being awesome because I can help her with Destiny and she can help me with Overwatch and Fortnite. It's a lot of fun to have different games that we love to constantly play, and we love online living games and loot chasers.
Almost anything that has multiplayer co-op. My favorite of all time was playing through the whole Borderlands 2 campaign and DLC together. Normally, we fire up lots of Mario Kart (especially Double Dash!!, where we can be in the same car), Bomberman, Portal 2, Seiken Densetsu III, and probably a bunch of others I'm forgetting.
When something doesn't have a same-screen co-op mode, we're likely to hand the controllers back and forth. We'll take turns in Overwatch and a few different RPGs, music games, and platformers.
I want to stay married, so nothing.
While my SO and I are both huge gamers, our gaming tastes actually very rarely match up, so we don't play much of anything together. We did TRY with a couple games, though... We did attempt co-op in Donkey Kong: Tropcial Freeze, but lo and behold re both REALLY sucked at that game, so that almost ended with me trying to strangle him. Then we tried Overcooked, which... well, if you have played Overcooked with someone with an hour, I'll be surprised if you're still friends or in a relationship with that person. So, like Keri, I'd rather stay in a relationship instead of ending up a stalker like Tyler, so we don't play games together.
My wife was never a video game fan until I introduced her to the Karaoke Revolution series and Singstar. We have spent countless hours entertaining the neighbors (whether they wanted it or not) by belting out some of the greatest hits in these games. Before the kids left the nest, we would have game nights where duets and battle contests could be heard for blocks. If I have to sing an Endless Love duet one more time, I may go insane, but if that's what the wife wants, that what the wife gets.
My SO and I typically spend the most time playing Rocket League and Overcooked — the two bright and breezy crowd pleasers. There was that one time we attempted Helldivers together, but that proved to be more frustrating than anything else.
I mostly play hide-and-seek with my significant other. I'm typically outside of her window, and then she sometimes even calls in the cops to really make it a party. Sometimes they scream something about a "restraining order." I'm not sure. It's hard to hear with all of the sirens going off. Oh, this was about video games? Sorry. Anyhow, I'm very alone and have nobody to play with.