Take many trips together. Write love notes to each other. If you want to have a good marriage, you have to work at it. It is not automatic. You can learn much from older happy couples.
Many churches offer classes and seminars to help married people with relationships.
Marriage is not for immature or irresponsible people. In marriage, there are some privileges, rewards and advantages, but the responsibilities are tremendous. Marriage is not a 50-50 deal. It is total commitment. So, take advantage of Valentine's Day, and do something very special for your mate.