I think this is probably the number one reason people get divorced - not because of money or infidelity, those are just by-products of the idea that a spouse feels like they married the wrong person. I can tell you now that asking God into your relationship before you get married and making sure the person you marry is who God wants for you is incredibly important, but once you are married, it's God intention that a marriage stay intact.
We all know as Christians God didn't intend for marriages to end in divorce. So, what happens when we start to get the feeling you are married to the wrong person?
When you marry someone, you spend the rest of your life with them. The rest of your life is a long, long time. I think it is normal to go through periods of time where you feel less close to your spouse, or your lives start to change and you feel like two different people than you were when you got married. The less time you spend together, due to work schedules or kids, usually adds to this feeling of separation. I think in marriage, there will be periods when it's important to get to know each other again. People change several times in their lives and as people in marriages change, it's important to communicate with your spouse about your feelings and opinions about things. This is all part of God's plan for your marriage - to know, love and respect your spouse. But it has to start with communication.
God wants your marriage to succeed!