I can relate to your feelings. I'm going through the same thing. Once he knows you are there for him without him commit himself to you, he has no incentives to earn your affection any more.
My feeling of rejection is strong. The difference between our situations is that he and I never really dated. He confessed his feelings to me 4 times prior to his rehab and getting clean efforts. One time he said he wanted to fall in love, he wanted wife and kids and he wanted to get to know me; then he said he can't wait to have a family and he is genuinely interested in me. And before he checked himself into rehab, he asked me to go out with him when he comes out. Now I waited on my end for 1.5 years during this periord he went through 2 relapses and finally styaed clean for about 9 months. He then reached out to me telling me that he wants to keep in touch with me and he's always found me an interesting person and he wants a causal approach for now. Then he gave me almost 0 attention. I cannot emotionally control it so I sent him a lot of messages hoping he can give more a little more attention or just be very clear with me. I turned down dates becaseu I wanted to keep my promise of agreeing to date him when he comes out of rehab.
Now he's annoyed by my messages and desire to meet in person more. So he just sent me a message telling me that" I don't know where you got the idea that we were somehow dating or something ,but that is definitely not anything I have had in mind. I need to focus on myself right now so I can give priority to my recovery. That's all I know"
It hurts so much coz I feel like my feelings are being played and I was led on.