If your ex-girlfriend has a habit of "bumping into" you a lot and showing signs that she wants you back, it's important to be able to demonstrate to her that you've moved on in positive ways and that seeing her again doesn't re-kindle your feeling for her anymore.
Here are some tips for showing her you've moved on while being respectful:
1. Act like you didn't even see her
If your ex tries to woo you in a crowded place despite you having made it clear that there's nowhere for this to go, act like you're too busy to notice her attempts to get your attention and go about your business. Don't show any signs that you care. The more confidence you gain in doing this, the easier it will be to deal with confrontations with your ex-girlfriend.
2. Keep the conversation short and to the point
If you just have to speak to her, keep the conversation short and sweet. Don't allow your ex to make you wander down memory lane and old times of love and tenderness. It's no secret that women want what's off limits, so stop her dead in her tracks with statements like "you know I've got a new woman in my life" and "Great to see you, but I've got to go!"
3. Flirt with another attractive woman
If she insists on flirting with other guys in front of you, try a little flirting of your own with another woman. Nothing is more irritating to your ex-girlfriend than to know you're playing the field and not at home crying over her! You can also try bringing along a female friend who is in on this and pretend to be together. Show your ex that you've moved on in the relationship department.