How do you feel when you see your ex happy without you?

JapanTomboy
Everyone says people feel sad/regret when they see their exs happy without them. For psychology purposes, what do you have to say?

Take your happiest relationship: they treated you great, you were happy, in love, and close. Then for some reason you broke up with them, leaving them heartbroken and a month later your friendship goes bad because of outside influences. If you were gone for 3-12 months (military, college, coma/hospital different city/state/country, etc) and came back to see your ex was happy without you, better looking, having fun and more interesting (became a model, got a job in general, became the "it" person, interesting new hobbies, etc) how would you feel?
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+1 y
I meant to say you broke up with them saying things like "I don't love you anymore/you're a loser/you're a lost cause/I can't stand your trust issues" or something like that, the other person still loves you, you have some love for them in your heart. Then you see them later much more improved and happy. What would you feel knowing they still loved you?
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+1 y
OK now let's say you guys were closer than anyone else you've been with, you saw them as the one, but took a break because of stress/personal issues. You feel lonely & be with someone else(why do people do that?)for a little while. This person convinces you not to get back with your ex with "reasons"(lies that make us question each other ie cheating). Your ex denies them & warns your new person will play/leave you. They do. Would you blame your ex? Feel stupid for losing them? Later forgive them?
How do you feel when you see your ex happy without you?
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