What you described is the essence of EVERY (new) relationship!
It's called the "infatuation phase".
Generally most new relationships start off filled with laughter, passion, enjoying each other's company, everything you want to do they want to do, talking on the phone for hours at a time, planning future events together. The word "no" is seldom if ever used.
It's no wonder one believes they've met their "soul-mate"; again!
I say again because if you live long enough and have multiple relationships you will discover that the "infatuation phase" is normal for the most part. People in the beginning tend to put their best foot forward, bend over backwards to impress the object of their affection in hopes of "winning them over". After there has been an (emotional investment) on the part of their mate and they feel secure in the relationship that is when they reveal their "authentic selves". Disagreements arise, boundaries are set, "deal breakers" and expectations are discussed. Only then do you learn if you have truly found your soul-mate.
With age and experience comes wisdom. Eventually you learn to ease into new relationships and allow them to evolve while maintaining your awareness. You'll come to realize the first 6 or so months is not what the relationship is going to be like.
It's always painful to be rejected or to realize you two no longer want the same things. However when it comes to love most of us (fail our way to success). If this were not true we'd all be married to our high school sweethearts!
Over time you'll remove those "rose tinted glasses", stop "romanticizing the past" and see the truth for what it is in the cold light of day. In hindsight there were clues and "red flags" ignored.
In order for you ex to be "the one" they would have to see (you) as being "the one". At the very least a (soul-mate) is someone who actually wants to be with you!
"Never love anyone who treats you like you're ordinary.'
- Oscar Wilde
If someone doesn't want to talk to you they don't think you're "special".