Realising you’ve put your all into relationships only to not get the same back

Hey everyone. It’s been a long week/month this period for me. I’ve been slowly realising the relationship I thought I had with a friend was one sided, I would always ask to make plans, and they would never reply. Or when they would it would slowly be breadcrumbs after breadcrumbs. And I’m starting to realise that there’s nothing I can do. We had a shared dream together, I wanted to help the,, and I did, I got them their first opportunities. Their partner would constantly tell me how good I was for him. He
Helping him. It was helping me. Yet this seems to no longer be the case. Phone calls going dry, text messages getting ignored. How can you do this to a person whom you’ve supposedly built a friendship with? What exactly seemed to have happened between the moments where we thought this would last forever? I was just talking to this with my therapist when I suddenly realised the pattern. I had kept trying, again and again, to try and talk to him. He would tell me how busy he’s been in the studio and I would believe him, and support it even. But slowly even this is ceasing. We are no longer the same. I cannot carry this friendship no more. I need to be free. I have tried to call again and again, he keeps on posting as if I don’t exist. This is ruining me and I’ll be damned if I’ll allow anyone to treat me like this again. Needed to get this off my chest. It feels unfair.