The article I mention just now, sexual intelligence. It states that many people have sex when they are tired. Normally people will do something that is important during prime time, like spending time with their kids, movies, hang out, work, exercise and so on. They leave sex for last, save the best for last doesn't work well for sex. When you are having sex after all your 'important things', you are normally exhausted. There are no more extra energy to make sex more exciting and satisfying.
This will lead sex life to a boring and routine status. When you are tired, you will have no time and energy to make sex fun, of course you won't be able to have fun as you are too tired. The next time when you hope to have sex and you won't expect much, your experience will tell you that it is just another sex that is so boring. Make a difference by just have this much earlier even in the morning, then the sex will be more satisfying and exciting. There are a lot more in the article other than morning sex, share it the next time.