J.R.R. Tolkien had an interesting take on this attitude. In a letter he wrote in 1941, he says this about marriages:
Nearly all marriages, even happy ones, are mistakes: in the sense that almost
certainly (in a more perfect world, or even with a little more care in this very
imperfect one) both partners might be found more suitable mates. But the real
soul-mate is the one you are actually married to.
It is odd, isn't it, how often our thoughts have no real base. We are, for the moment, unhappy in our marriage and we construct the idea of someone who would have been "better" for us to marry, someone we are sure would have been kinder or wiser or richer or whatever characteristic we currently don't like in our spouse. This is all moonshine and make-believe, of course, but it can be a source of real discouragement.
Tolkien's attitude is the correct one. Of course there are people with whom I may have been a better husband or have had a better marriage, but this is the marriage I have, the one God has allowed for me, and the one in which I am to serve and find meaning and purpose. The woman with whom I sleep is the soul mate with whom I share my life.
If you find yourself discouraged someday, thinking of boyfriends you did not marry or of other husbands who seem better than yours, do not try to talk yourself out of this feeling. Feelings, of course, do not really respond to being "talked to" very well. This is your marriage. You have the chance, and the calling of God, to be an Excellent Wife in this marriage. You may serve (and are commanded to serve) both God and others in your marriage. The man to whom you are married is your man and your soul mate.
I may sit quietly at night and think I should have chosen a different career, or a different house, or a different car, but I have the career I have, the house I have, and the car I have. I also have the wife whom I chose and married. She has the husband whom she chose and married. God has made us one.
So, let your moment of thought pass. Then get back to serving God.