it depends on alot of things. are joe and jake really good friends? and how long have he and sarah been together anyways. Alot depends on if its that serious or not. i would sit back for a while and let their relationship break up on its own, like it sounds it might. that way you don't get the blame for any of it. after that, if you think its necessary you could always have a talk with your friend jake to tell him how you feel about her. or whatver you think is right. just go with ur gut on it. everything's far in love and war.....