How do you live with lactose intolerance?

Avoidance. Lactose intolerance is the inability of the gut to digest the disaccharide lactose. There are replacement enzymes you can take orally. The effectiveness varies. Avoidance of lactose remains the primary treatment. In general, it takes a fair bit of lactose to induce symptoms.
Avoidance. Lactose intolerance is a permanent condition. The treatment involves avoiding lactose products and/or using an enzyme replacement. There are products which are lactose-free; dairy free may not be free of lactose. A helpful trick is to buy products from the kosher section which are non-dairy as these will be also lactose free.