It takes time for people to grow apart. It is the culmination of hundreds of separate choices made without reference to the health of the relationship. The partners go their own ways in activities that are most engaging, and save the mundane things for togetherness. The relationship can become associated with boredom and tedium.
In the same way, it takes time for people to build a strong foundation of mutual growth and vitality. This is meaningful time that a couple chooses to spend together in pursuits that are stimulating and challenging. Growing together instead of apart requires that you share life's learning curves with your partner, day after day, in a variety of ways.
Perhaps your partner plays golf, runs, skis, or boats. You may not have any background in these activities, but you can certainly learn. You may not have the physical ability or find that an activity doesn't grow on you. But you can appreciate what it takes, and be an active supporter in a variety of ways. Your partner's area of strength may be intellectual; it may be artistic; it may lie in home maintenance. Just participating alongside your partner gives you the opportunity to learn new skills and appreciate more about your loved one.
By the same token, share your own strengths. It may seem easier and more efficient to avoid the explanations and coaching time involved in sharing your strengths with your partner, but ease and efficiency don't necessarily feed mutual growth.
If you're both readers, read the same book, either separately or aloud to one another. Talk about your reactions to it. The content of the book becomes a shared experience that draws you together. Take up a new activity that neither of you has tried or mastered already. Sign up for dancing lessons or join a bicycling group. If you enjoy travel and have the means, plan trips to places neither of you have visited. If you're social types, make new friends in common.
With each choice to learn and grow together, you build a history of mutual support and an inventory of engaging activities that bond you and make you interesting to one another. By comparison, the things that lead to stress and friction will be boring. You won't want to expend any energy on them.
Read the Same Book 
