Be honest here please!?

so ill make this short & simple. I like this guy, but hes had a girlfriend for the past 2 , almost 3 years. from what i hear there very happy. shes super pretty & i guess has a lot of friends & a great personality. from antibody's personal experience, is there even the slightest chance they might break up? i really don't think that he likes me, maybe just good friends? thanks so much ahead of time!