Honestly, sounds like you're dodging a bullet
If you don't see it going anywhere, why are you stringing him along?
Just be honest with him and if I’m honest I’d cut ties with him. No point stringing him a long if you see no future.
I think if you were clear on what you wanted before having sex with him then he probably wouldn’t feel the same as you’d have stated you’re looking for a mature partner that will always be there for you and you could have told him your wants in a relationship. Having sex and then saying he’s not got qualities that are partner worthy then of course he’s going to feel that way as he obviously does want more. And if he hasn’t changed then respectfully break it off and say it’s not what you’re looking for.
Im not intentionally stringing him along because initially I told him I didn’t want anything serious/ long term as I am rediscovering myself, my teens and early twenties I was in a long term relationship. Which he KNOWS! But we had become closer as friends especially 2023 Dec- Feb 2024 because my relationship was very rocky and in last stages of second pregnancy so he was someone I was very close to and then last year we decided to be casual partners that do couple like stuff but exclusively us two without the titles (just more bad decisions it seems but made sense at the time).
Yeah he doesn’t sound like an ideal partner. Just be honest with him. But honestly why waste your time on him anymore if you don’t see it going anywhere?