My wife and I go to spinning class a couple mornings a week. It's something we like to do together, and I feel like I benefit from having a regular workout partner. Some days I'm just lazy, or I don't want to venture out in the pre-dawn cold, but having a supportive partner motivates me. She bolsters my self-discipline when it flags.
Or does she? Is it possible that having a supportive partner might have the opposite and paradoxical effect, actually undermining effort and commitment to health and fitness goals over the long haul?