Crushing on a guy, but we're both in relationships?

Peter is a good friend of yours. You see him as a great guy and he's now in a relationship that he's very happy in. You on the other hand are in a relationship that's going down hill fast. You've become somewhat jealous of what Peter has and wish it were you with him. You could end your relationship with Luke and try to steal Peter away from his current girl friend but if you tried this would Peter respect you as a person? It's very hard to tell. The only way you could is if Peter were to express an interest in becoming more than just a good friend with you. Even if you don't end up with Peter it may be time to end things with Luke. It doesn't sound as if you're being fair to yourself or Luke right now.