I have felt before like I keep casting my fishing line into water, the fish takes a nibble but doesn’t bite and keeps swimming away, back and forth nibble then not bite. Eventually I realized it’s a fish I can’t reel in and gave up trying. Literally, there are other fish in the sea.
Seeing a therapist is always a good idea and may help you sort out your feelings.
Ugh, I had a relationship like this one end with a haunting lack of closure. I was stood up for a date after a few years on/off and he never called me again. In my day of dating, we only had phones (and doctors or drug dealers had beepers— this guy had a beeper and was not a doctor

). I was proud of myself for never calling him again either, because I understood that his dumping me like that meant he didn’t care for or want me. So I moved on.