I'm grateful for my neighbor down the street who also loves getting in a good run before her morning cup of joe. Having someone to exercise with can give you that extra push you need to lace up your sneaks. When choosing an exercise buddy, it's great to find someone who is at the same fitness level as you, but it's not imperative. You really just need someone with the same level of commitment. You want this to be an equal partnership where you're both on the same page about how often you want to work out. A good exercise bud won't bail on your post-work spinning class and try to persuade you to have margaritas instead.
You definitely don't need to be loyal to solely one fitness partner. It's smart to have more than one buddy for all your fitness needs, as long as they're as driven as you are to stick with regular workouts. If you find a fitness partner who's way more athletic than you, who's idea of an easy run is eight miles rather than three, then meet with them once or twice a week when you need your competitive buttons pushed. If you feel that your partner is not as fit as you, then make a fitness date on days when you need a leisurely workout in between intense ones. The more ways (and people) you have in your life to motivate you to move the better!