There is no Maddam Rue down at 34th and Vine, selling little bottles of Love Potion #9, that is not how it started and that won't be how its fixed. Forget what you have learned from a culture corrupted by sin and return to the word of God.
For the true believer, the born again, follower of Jesus Christ there is a much bigger problem if you are not "in love" with your spouse. If you are not in love with your spouse , chances are, you are not in love with your Savior. Whaaat?
Think about that for a minute. When you love Christ, you will be a person of forgiveness. In fact, when you love Jesus you will not only forgive people who wrong you, but you will also be compelled to love your enemies. Hopefully you have not made your spouse your enemy. It happens, spouses become enemies but that happens because the souses stop loving God, first.
Your first love should be Christ and with the love of Christ living in and through you, it becomes so much easier to love others especially the one you committed your life to in marriage.
Before you run down to 34th and Vine, have a little talk with Jesus first, I think you will find the problem with you loving your spouse probably began when you started drifting from a love for Christ.
A lot more to marriage than this, but this is a major start.