Ah,
another long distance relationship (LDR) that came to an
unfortunate end. Well, by now, you ought to realise a few things
about LDR:
I) Discipline of all forms must be instill, from both party, for
without physical presence, the other party isn't here to cater to
your possible needs. If not, the likelihood of breaking is very
high.
II) LDR is not your usual, common and normal kind
of BGR relationship you are leading; everything must be twice da
effort.
III) Main reason why LDR fail is almost always because of the
failure of (I) from one party, which result in the dating of other
people, in consideration of a potential
parter.
P.S: Even if you were to propose - its utterly foolish to do it
right after your come back. You just never know what has really
happen during this period of time. By the way, if she can't even
survive the test of this transitory separation, do you think she is
in and ready for marriage? 
Cheers