I've said this many times too because I know from personal experience that it takes a consciousness and conscientiousness to become and remain the right mate.
As I write this, I recall a joke shared by a pastor on the "definition" of complete and finished in the context of marriage. He said:
When a you're married to the right person, you are complete.
If you're married to the wrong person, you are finished.
If married to the wrong person from the wrong family, the person is completely finished.
I pray that all those who think they are married to the wrong person, make an attempt to "become and remain" the right mate - and you'll see postive changes in your marriage.
Someone wisely said: when you get to the heart of the matter, you'll find out it was all a matter of the heart. Marriage is God's idea, please do what you can so your heart is right with Him and you'll see it will be right in every other area of your life. If you haven't already done so, give your heart to God...you'll be completely complete* when you do. God bless
*"...You also are complete through your union with Christ." (Col 2:10a - NLT)