Listen bud,
Everyone here has told you that seeing her is a bad idea. Why aren't you listening?

she says I am her best friend- ok, you are her best friend. It doesn't mean that SHE wants to DATE you, and is in LOVE with you. Why do you want to beat your head against the wall? You DO remember Charlie Brown and Lucy pulling the football away from him don't you?

Tell me, if she loves you, why does she want to be with other guys? Because she lacks the attraction she USED to have. - YOUR words, dude. If that is the case leave her and move on. She's doesn't want to TRY and get it back, she wants to continue to USE you, and you let her.

but I just need to know that I am a good person- how will you feel like a "good person", if you try and find out from a person that is using you, and abusing you??

Never mind the abuse part, she's not abusing you..........YOU are abusing yourself.