What does it really mean to be content, and how can we balance being satisfied with still wanting to achieve our goals?

My partner is always on gambling sites. Could he possibly be cheating, chatting to other women, and the winnings he always says forfeited?
What makes it difficult to truly know what's going on in another person's head, especially when it comes to boredom-driven actions?
As someone who acknowledges everyone fights unseen battles, how do you personally choose to approach kindness in your daily life?