even as odd as it might sound for a boy to admit it, i really loved her.
Helllooo?? And when did it become odd to admit u love a girl?. . . if you's not on some ego trip

i stumbled on some voice messages of her ex demandin sex n all from her. he actually said somethin bout enjoyin doin it and wantin more.
Case in point: I have numerous friends who're happily married now. One calculated text msg from me thanking her for some phoney sex romp would cause a major crack in those homes especially if there're fundamental trust issues already.
I think your judgment here was rather rash though I don't blame u so much, some guys I know would've fractured a few bones of hers.
she denies it
Does this mean anything to you?
What to do: Call her and apologise. I refuse to believe u're 100% a saint yourself.
Set the conditions as u'd have 'em . . . what u can't take from her (if u'd have her change her # to forestall further incursions by the intruding moron then tell her), what u want from her. . in short communicate.
Put the past behind u n' give her a clean slate to start with.
Her actions thereafter will then determine how things progress.