Quit being in a relationship that can’t help your growth in life just because you’re afraid that you won’t find another man or woman like him or her. The person you might be with could be abusing you, or doesn’t respect you.
Is that the kind of person you want to spend the rest of your life with? God didn’t bring you on this earth to be treated badly by people. He wants to give you the best. Let go of the person that is always making you sad. It’s not good for your health.
If you’re finding it difficult to let go, I would advise you to find a genuine pastor to talk about it and to help you in prayers. Your strength needs to be renewed everyday. Allow the Holy Spirit to fill you.