I would say it's got to be love that is the biggest motivator for everything you do. When you love each other, you will make sure that your partner is ok a d taken care of. You'd be more willing to make sacrifices and not take your partner for granted
Expectations are driven by beliefs and values... both of which are created by upbringing and life experiences.
I know people who will overlook physical indescretions as long as there is emotional fidelity (not me mind you but I do know a few people like that)... that's a whole different set of spousal expectations. Where do you go from there? I expect my spouse to cook my breakfast and look good doing it? LOL