Stop trying to avoid hurting your partner. People have feelings. They're supposed to have feelings. As humans, we sometimes feel scared, angry, and sad. If you hide the fact that you love the way a certain guy smells because you don't want to make your partner jealous, you've just robbed him of an important piece of information. He might feel jealous... but he might also want to wear whatever cologne that guy is wearing!! Or take a shower just before you come home from work!" Give yourself permission to feel whatever you feel, and let your partner feel whatever they feel.
Create a relationship structure that you can actually live by. Don't make promises you can't keep and don't enter into agreements that make you feel like you are giving up a piece of yourself. How about marriage vows based in reality...something along the lines of "I promise to love you, until I don't." Or even better, "I love you right now. I want you right now! I don't know what the future brings, but I'm ecstatic that I'm with you in this moment." All marriages end, either through break up or death. The point is to enjoy it until it does.
Reveal to your partner any past indiscretions, and clean up any current problems as soon as you recognize them. Keeping secrets destroys the connection in a marriage. We all make mistakes. Hiding those mistakes keeps them in our consciousness. They lurk in the back of our mind, egoic proof that we screwed up...proof that we aren't one hundred percent lovable. Instead, bring your mistakes to the forefront, divulge them to your partner, and deal with them so you can let them go. This is a form of true love.