First of all, if you run at different paces, it may be a good idea to only stay together at the beginning of a workout together or the end. If one of you is a faster runner, you may get irritated having to run at a slower pace. And, actually, it can be harmful to you. So, plan to just run the first mile (it will be the warm up for the faster runner) or the last mile together.
Another variation of this is if one of you runs farther than the other. You can run as far as one of you wants – and then the other can continue on their longer run. This can be done by doing a loop around your neighborhood and then dropping one of you back at the house. If you go somewhere to run – while one is running farther – the other can make a water run.
Don’t try to be your spouse’s coach during your runs. Barking orders at them can only cause them to roll their eyes at you and be silent the whole run. If they ask for your opinion – that’s one thing. But, if you are constantly trying to get them to run faster, breathe differently, etc; – you will end up running by yourself very soon. A better way is to wait until after your workout and then casually say, “it may help you if… “
If you run a road race together, you don’t want to compete with each other. Instead, you want to encourage each other and cheer each other on to their best race possible. Racing against each other will only cause resentfulness later on. Just be each other’s best cheerleader.