Yes, I skimmed a couple. If I'm not mistaken he was very attracted to this woman and was curious about proposing despite only having known her a short while. Despite his affection for this woman (not sure if it's the same one), he was lacking the confidence to commit to marriage at that time.Actually, the prehistory - or backstory - is rather more nuanced than that. Some of the previous threads where he described this relationship at an earlier stage are - perhaps - worth taking a look at.
That situation to me all sounds very premature- break up with a girl, rebound with another, and experience a "honeymoon phase". Honestly, I see no need to rush into marriage. In my limited and biased observations, young men who are quick to propose do it out of fear that they will lose the girl somehow unless they lock them in.
Steve mentions in an old thread his GF at the time is afraid he cannot commit to him. I think it would be highly advantageous for Steve to reflect on his past relationships and honestly assess why they failed.
It's evident to me reading through some of these threads that the OP has a lot of insecurity, self doubt, and indecision. That probably has to do with self esteem and anxiety, and possibly even OCD.
Steve, if and when you go to therapy (which I would highly reccomend as this situation is not over), I think you will find that your own self doubt, insecurity, etc likely self sabatoge the health of your relationships.
Let me give an example. I have a friend who is extremely neurotic, 10x more than me and I consider myself pretty bad. My problem is I'm overly meticulous, a perfectionist, and never feel fully satisfied with my acheivements --and I'm way harder on myself than others- probably a result of how I was raised. His issue is self doubt. He is very charming and can be in a fantastic relationship with a great girl, but he incessantly questions whether the girl actually loves him and if she is cheating on him or is upset with him. And that insecurity creates mistrust, and that mistrust creates resentment for the girl. The his relationships go up in flames like clockwork, time and time again. I suspect you have themes of self sabatoge as a result commitment issues in your relationship history... and probably other areas of your life like school, works, hobbies, etc.