why do you marry a person in the first place? If I'm not mistaken it is because you love her/him and you want to share everything, good and bad. And if you're asking yourself this question whether a marriage will improve or make the love bigger, then don't get married. Mariage is not the solution for keeping the love between two people alive.
Mutual respect, trust, being able to say you were wrong about something, to have the ability to communicate with each other about every issue, these are just a few things that make a marriage work and out of all this comes love.
And why shouldn't women be able to marry someone younger; if two people fall in love with each other, does age matter?
And of course we can look at other men/women, why not? God gave us eyes; does it mean we're unfaithful only by looking at another person?
So only if a woman "does her duties", the man will love her more? A man and A woman get married, they are in it together, so both husband and wife have to make it work.