You're not using enough face wash. The first time you use your brush Dr. Robb recommends filling the entire inner circle with cleanser (about a quarter-sized amount). Then, you can adjust accordingly for your skin type.
You're not using enough water. Just like your toothbrush, you need to thoroughly soak your Clarisonic in water to get the ultimate pore-cleaning action.
You're sharing your brush head with your partner. Even though the Clarisonic doesn't harbor bacteria, you would be swapping genetic material in an entirely new way. Just get them their own brush head. If the deed is already done, soak your brush head in rubbing alcohol for a few seconds.