My parents have been married for 35+ years. Dated for 10 years.
I do not think folks understand marriage is work. Sometimes you have to put aside what YOU want for what the FAMILY or WE want. Plus, you have to have a plan, communication and everyday is not rainbows, love and romance movies. Trust and Respect are huge in a marriage, plus keeping your business about the marriage, within the marriage. Also it is not bad that everyone has their own television. Respect each other's personal space and don't restrict a person from doing what they love professionally and personality. You must be supportive of each other's goals and how they benefit the family has a whole.
My parents marriage is far from perfect, but these are the things I have learned from their marriage. Nothing is instant and nothing is self gratification
Also my father recently told me he decided when he HE was ready for marriage and before he married my mom he told her the things in a marriage he was not going to argue about and he has held on to those rules.