Those are the only two things I've seen work. If #1 turns up nothing, then proceed to #2b. And in the meantime, GAL your ass off, and become the better option. Best case, you'll attract them back, and at a minimum you'll become a better person that will be more attractive to SOMEBODY in your next relationship.
Oh, and of COURSE she says they're "just friends." ALL CHEATERS LIE -- PERIOD. The sooner you come to grips with that part of this, the better you'll be able to operate going forward, bk.