we don't know what happened after she went back to etheria... she may have eventually beaten hordak and won over all of etheria for good. then, she'd be free to go wherever she wished. we know that both he-man and she-ra were able to travel between their worlds with the help of the sorceress, so it's not like they never saw each other again.
she-ra/adora knew there was a huge responsibility, and she wasn't going to turn her back on her etherian friends because she was selfishly going back to live with her royal family. she had a higher calling, and she stepped up to it. she didn't let her past overcome her, she used her experiences to make a better life for herself and for everyone around her.
yes, being stolen away was a tragedy, but instead of dwelling on all that, she moved past it and made an incredible difference on etheria.