Most Helpful Guy
You need to make a decision here because you can't have both men (well you can, but shit will hit the fan sooner or later). Just beware that you will be ruining a 'friendship' if you choose to leave your boyfriend for his 'friend' but you have to do what makes you happiest.
Most Helpful Girl
You've been with your guy for 5 years, and now that his friend moves in, you want to leave for him. Well guess what? You only like his friend because he's close to you, he's 'there' for you. Yea, sure he is. . . obviously a real good friend, hitting on his buddies girl. He's there for you in the way that he's knows he could potentially F you sometime. So he'll be the nice guy, the guy you should be with, the one to comfort and listen, so that when you break up with your guy, guess whose shoulder you'll be crying on? This is so predictable it's sickening. The spark doesn't last forever and it takes hard work to keep a good healthy relationship where both partners needs are being met. I'm sure there is plenty of fault on your end too (like thinking of leaving him for his friend). Leaving him for his friend would be nothing but being a shitty person. I highly recommend you don't take that route. The grass is not always greener and I guarantee you Mr. Wonderful isn't as great as he seems.