Don’t allow yourself to be trapped in a relationship with someone who is not capable of giving or receiving love. You can’t fix someone else. They must acknowledge their problem and really, really want to be fixed. They have to do the work - with a therapist. I speak from experience.
Even if you just met someone online and have had only a few dates, there are signs. I dated and attorney for three months and realized he was just like my ex. Bottled up inside. Aloof. I never felt relaxed around him. It was never clear what his expectations were.
For sure many of the signs are subliminal. Listen to your heart and your mind. And above all - do not let the fear of not finding someone else stop you form doing what your heart tells you is right for you.
After I broke it up, I laid in bed for a several days with those fears. Honestly, I felt paralyzed. I had to remind myself over and over that it is better to be alone (for a while at least) than to be with someone who would make me miserable. And I ran it all by my two best girlfriends. Outside reinforcement.
This was around the time when the song "Somebody That I Used to Know" was popular. Sometimes there is comfort in having a song. I listened to it often during that time.
Bottom line - if you feel trapped - take a close look. Search your heart. Listen to your heart. Have your pity-party. Cry your heart out. Have a glass of wine with a friend. Then move on and never look back.