milkyhighway: Overcooked games are good fun. Very make-or-break for relationships though. :P
Nice thread with lots of good titles already suggested. I'll add onto the pile if you'd like? :D
Hyper Light Drifter (GOG is yet to update the store page to reflect this)
Enter the Gungeon River City Girls Slipstream Swords of Ditto Children of Morta Wildermyth (if you like reading, and taking turns)
Monster Prom and its sequels (again: if you like reading, and taking turns)
Already recommended, but I'm also vouching for:
Kingdom: Two Crowns
Crawl
LEGO Star Wars and Harry Potter
Lovers in a Dangerous Spacetime
Worms games
Metal Slug games
Fight'N'Rage
Also: have you ever tried taking turns playing single player games?
We often do it and enjoy it a lot. Lots of opportunities for cheering each other on when it's the other person's go, and sympathising during failures. And if it's everyone's first time with the game, can give you something new to talk/speculate about.
It's a different way to bond than playing co-op or versus multiplayer. And also very different from experiencing single player games on your own.
Obviously not going to be to everyone's tastes though... Some people compulsively backseat game, for example. :P
But that can be an opportunity for relationship building too - learning how to tell someone to shush while you figure it out, ahaha!
I love the Worms games for a gaming party.