Just as running the same path by yourself day after day can get pretty boring, running the same path with your significant other can be equally as boring. We all tend to like routine because it is easy, but routine gets us into a rut, even when we're with someone else.
Next time you and and your husband (boyfriend, friend or whoever you like to workout with) take on exercising together, take turns making a seven day plan.
Here is what my husband and I do:
Day One: He chooses the route we run.
Day Two: I choose the route we run.
Day Three: He picks a mode (running, biking, etc) to do for an hour or so.
Day Four: I pick the mode we do for an hour or so.
Day Five: He picks a relaxing activity.
Day Six: I pick a relaxing activity.
Day Seven: We get to tell each other what to do for 30 minutes straight. For example, I always make my husband do a set (or two) of lunges because he would never do them on his own. He thinks it's a good idea for me to do pull-ups, something I would never do on my own.
The only rules are: It has to be fair, it has to be physical and it the other person has to do it.
We tend to get competitive to see who can come up with the best ideas, which means things are always interesting. Also, we tend to keep our ideas a surprise until that day. This way neither of us can complain about what the other person has chosen.