I absolutely love and respect my husband more today than 10 years ago when we got married. We get along better to. Chemistry still alive to boot :)
We have never felt any desire stay together because of the kids, or because of a vow. I'm not sure that humans are biologically monogamous creatures who naturally stay partnered for life. It takes effort for that to happen. And life is to short to stay in that kind of dynamic.
So, we acknowledged that if we are to stay together it is because we each wake up each day and choose to do so. This not only keeps us from feeling stuck, but it also keeps us trying. We still flirt and work for our connections.
Every year really gets better. That said, we didn't have the "grand romantic start" many couple do. We actually grew into our love for each other. To start, all we had was chemistry and physical connection.