Dear Peacely, (Gonna reply this before I dash out of my
house)
What you are doing in your previous relationship with him is that
you are trying to shape that perfect lover with a mortal. In
reality: there is no such thing as the perfect lover, the best bf.
No doubt, you have high standard - its prefectly alright and good
because at least you know what you want. However, what's the use if
you get a guy-ready made package, implanted with every single good
elements you could ever dream and find in a bf. 
Let me tell you, in the end, you wouldn't treasure him at all and
in fact - there is no such guy.
Don't ask him to change - seek improvement. Don't growl, nag and
blame on him about his lousy life, etc - hey, you are his
girlfriend and not his enemy. Since you
are dissatisfied with his way of life and wants him to improve -
shouldn't you encourage him? Guide him along and it will be
reasonable because you both grow, mature and walk together, rather
than a separate path which initially you seek to stroll.

Scolding from your good galfriends? Disgrace to woman race? What
rubbish. You know something? By statistic, the percentage of woman
not having the man they love and falling for the wrong person is
because of the passiveness they react to relation. THERE IS
ABSOLUTELY NO WRONG in seeking for your own happiness - you lead
your own relation - you ain't going to marry your friends right? So
why listen to such words which I find it utterly rubbish?

You rather have a thousand guys, you don't have feelings for,
chasing after you OR you rather take initiative to know a guy that
capture your heart?
Advice? 
Your bf is a good guy, from the post I see - you want to let his
relationship blossom, you have to put in the effort, and not like
the previous times, critizise him, putting him down and
acting-princess (xiao jie pi qi). 
First thing you must do: show appreciation. He has accepted you for
the way you are and went through your nonsense phrase - isn't it
the time the show your appreciation for his patience and character?
Do something, write a letter, express your feeling, etc. You have
to make him feel WORTHWHILE patching back with you, at least the gf
he is having he improving. Nothing is more rewarding than to see
how your partner is growing from the relationship. 
Second thing is have to do: Avoid critizising him and destroying
his self esteem. You want a guy who succeed in life don't you? He
won't because of what you are doing - how on earth can he get his
confidence from if EVEN HIS GF damned him? Guide and walk together
with him. If there is something about him that pissed you, tell him
and improve TOGETHER WITH HIM. It wouldn't work if you were just to
SAY him and do nothing. Its like if you ask a crippled to walk and
never lift a hand to assist. Remember you are his gf - not you
wouldn't be his source of stress. 
He is your first bf - no doubt alot of things you wouldn't know
until you ended this relationship. Well, this is a second chance to
this beautiful relation, if you did your best and put in the effort
and be a reasonable gf.....
but i m not sure if it will last.
.... does it matter? Things that you have put in the effort - you
will be rewarded on your conscious and in the shrine of your
memories, sweetness will flow. 
Quote of the day: Many a times, we wasted too much time looking for
the perfect lover, when in fact, we should be perfecting the love
we have. 
Cheers