Know Your Partner
A soulmate isn't necessarily a sole mate, and running with someone you love isn't a guarantee that he's as fit or fired up as you are. If you aren't evenly matched running partners, there are some workarounds that can make your couples-running productive for both of you. Do your "speed work" at a track where you can each go at your own pace but stay in same general proximity. Plus, you can always warm up and cool down together. On your easier recovery days, you can run side-by-side anywhere -- recovery runs are supposed to be done at a casual, aerobic pace anyway.