x2....
How many days she hasn't contacted you? 1 day izit?
Guys usually (not all though) hide into their own world when they
are suspicious, have doubts or problems. They make decisions in
their 'own caves' based on their presumptions.
If the whole matter is not what you think, have
you ever think the hurt and scars she's gona get if you have
mistaken her??????????
The decision is not just yours only if you love
her, and don't make avoidable mistake which you will regret. You
can't reverse them.
Talk to her first. Tell her about how u feel...e.g. insecure with
her talking to her former crush. Have to be frank with one another.
You, she, like any normal human being (any of us here), are and is
entitled to have friends. Moreover, she just chatted AN
HOUR with him on msn!!!
Both of you have your own needs so talk through and sort them out
SLOWLY and RATIONALLY. No time is a good time, you don't tell her,
you suffer means relationship suffers, she wonder wats wrong wif
u..she also get affected... 
But personally, I can guarantee when things become
clearer, they do become a lot a lot easier to solve than you think
right now. 
She is insecured and so are you even more. Building n learning to
trust needs two and it takes time, understanding n efforts. Give n
take as well....
Are exams and character mismatch excuses
not to face the fear that the truth is what u
suspected???
Juz wanna ask... will a childish and cutish girl ever grow
up and mature?
Yes, like any normal human beings....pacifier no
more 
