Time really do heals a broken heart. Trust me. I've been through
it.
U may still keep her photos if u want, and it will be unavoidable
that u will think of her once in a while. Afterall, the both of u
had good wonderful memories together before.
Get involve in activities, get busy with work/studies, etc. I know
it is hard to being single again. But do remember that u were
single once before the relationship and u had got on fine. So u can
make it through this period.
However do take time to search ur own feelings. Since ur ex had
left u for another guy, if there is an instance whereby she comes
looking for u to patch up, would u take her back? Or would u take a
stand and just be normal frenz? Keep in mind that if she can 'run
off' with another guy, she might do it again.
The answer lies with u afterall. So search ur heart and avoid her
for the time being (if she still contacts u). Let ur feelings
settle down first because u would be in a very confused state now
and u wouldn't want to jump into some silly relationship right
now.