It is not worth assuming that all couples who stay together have strong and deep feelings for each other.
Many people live for years only out of a sense of duty or for other reasons that have nothing to do with love.
Everyone gets tired of each other sometimes. However, it is worth monitoring your emotions: if you feel relief and joy when your partner is not at home, then it is worth thinking about your feelings.
It's possible that you've simply stopped feeling love.
A loving person enjoys taking care of their partner and making their life better. If you feel like you just have to and are obligated to do this, then the warm feelings are probably gone.
If you start thinking about what will happen in a potential breakup, this is not the most positive sign. It is quite possible that it is simply a matter of fatigue.
However, in this case, you need to find correct ways that will help refresh your feelings.