Partner for a peach faced loveird

[Natalia Shishkin]

My daughter has a very social peach-faced lovebird. The bird is 1.5 - 2 years old and spends most of the time out of her cage. She has lately become more aggressive, has been shredding a lot of paper, and guarding a couple drawers as if it was a nest. Also, she was terribly lonely two weeks ago when we went away for a week and a relative was taking care of her. We would like her to have company but don't want to lose her as a pet. Unless we have to, we don't want to have chicks. What would you recommend? We considered getting another female or maybe a younger male. But it appears risky based on what I have been reading.

Thank you,