I read your original post you linked and now this one. I'm so sorry that you're feeling so raw and emotional right now, but it doesn't seem unwarranted at all. It's been 8 years together, it's completely reasonable for you to expect and want these things especially since you've been clear about these expectations and wants the whole time.

I don't think he's going to propose. He's comfortable and perfectly fine as is, that's clear. You've made your feelings clear, especially how it's affecting you in the last 2/3 years. If he knows this and hasn't acted on it, it's because he doesn't care. I think you should leave him.

I started dating my partner at 24, he was 22. I told him then and I still believe it to be true now, if you've been dating someone for 5 years and still don't know if you want to marry them, the answer is you don't. 5 years is a long enough time to really get to know someone, let alone 8 years.

His message to you is so infuriating. "I told you I want to marry you" but none of his actions have shown it, not once. No promise ring, no established timeline for when you'll be married by. He's stringing you along because he has it good this way.