Here we come to a myth that sends people down the road into astonishingly ridiculous situations in which they often return bewildered or unhappy or even hostile.
You've no doubt attempted some major project with your partner, thinking it would make the two of you closer.
Perhaps you and your partner have a great common interest that makes the two of you happy. That's fine. But the greater myth is that if you don't have one, you must find one in order to make the relationship more fulfilling. Hat's just not true. Some couple love their time together, they love being great companions, but they also respect each other's idiosyncrasies and don't feel they have to engage in lots of activities together.
It's not what you do, it's how you do it. If forcing yourselves into common activities creates stress, tension and conflict, then don't do it. It's wrong to think that there is something amiss in your relationship if you don't have common interests and activities. I promise, you have a number of significant commonalties that you may not think about. You live together, you sleep together, you eat together, and if you're married with children, you parent together. You may worship together, spend holidays together and even ride to work together. If it doesn't work for you to take ceramics class together, just don't do it. The important thing is that you not label yourself as deficient or having a less committed love because you don't share common activities.