I read Osho once about love. The thing that stuck out to me most was this thought: You can never get bored of your life partner if in every moment, you are present with them, and you do not make assumptions that they were the same person that they were yesterday. Your partner is an evolving being, just like you. Therefore, every day you have an entirely new lover. You must be present and avoid assumptions to see this. But as long as you do, you will never be bored, and you will remain in love for a long time.