adviser; someone to consult with; someone to turn to about one's concerns; confidant
先輩がよき相談相手になった。
My senior colleague became a good confidant.
彼は職場での私の頼れる相談相手だ。
He is my reliable adviser at work.
困った時に何でも話せる相談相手がほしい。
I wish I had someone to consult with about anything when I'm in trouble.