I'm just saying that I wouldn't go far as kicking a guy below the belt over the fact that he plays a silly video game that I may or may not dislike. There are WAY worse habits that someone can have, something like the OP should be the least of someone's worries.
I'm not saying that standards are all bad to have, I'm sure everyone has them to a degree(who'd want to end up with some psycho, as an example). If just playing a game will get you injured though, you're definitely with the wrong person, imo.
The only way a problem would really arise and it wouldn't work out though is if the play time seriously 'cut me off from him', as in he would: not get a job, played near 24/7, we couldn't do anything together. Now if for some bizarre reason a game led him to hit me, yeah all bets are off then.
Tl;dr Don't let a little hobby such as playing RS or another video game make you feel like you'd be unwanted. Just playing isn't hurting anything; maybe playing for loooonng periods(since you are pretty much 'cut off' from your relationship), but playing in general isn't some big evil.