Talk to your SO. Communication is key in every relationship. My hubby and I have been together since 98, and married since 05. We've broken up and always gotten back together. We've both done and said things we regret, but we are making it. We love each other very much. And you have to let each other know that EVERYDAY. If you want your relationship to work, do EVERYTHING you can to save it. Even if that means counseling. I know a lot of people, including myself, are against it. But I know if push comes to shove, I love him enough to do ANYTHING to save us. And if you're thinking the same way, talk to him, and tell him it has to be done.
Maybe see a couples councelor, or try to spice things up. Talk to your spouse more, and try to spend more quality time. Let them know how you feel. If there are that many years and two children involved, then its worth the effort to try to keep things going.