I find these assumptions wierd that if said partner play games you are gonna get along just fine because of that and have a "common interest". I have as can be labeled a "gamer boyfriend", there is a certain problem though because we have completely different tastes in games.
He is the fanboy-king of fanboys when it comes to blizzard, i.e. if blizzard made it it is automatically awesome.... - . - other than that he likes RTS games.
I can play the occational RTS and I have had my share of days in azeroth but in general I think that these games are boring beyond all measures.
I like the FPS genre, Quake, Unreal, Bioshock, among others, and then can go pretty fan-girlish over anything Bioware has ever made and over all love western RPGs.
While he on the other hand pretty much despises any thing with an FPS genre lable and a game without a multiplayer mode (most RPGs) is not worth his time.
Point is that the only real thing we have "in common" when it comes to games is the tool we use to entertain our selves, the computer. Kind of like two people saying "I like sport" but what it really means is that the first one likes basketball and the other one likes golf, but both of them can whatch their sport at the TV.