彼は彼女から離れていた。

he; him; his; boyfriend

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

she; her; her; girlfriend; sweetheart

from (e.g. time, place, numerical quantity); since; from (originator); by; because; since; out of (constituent, part); through (e.g. window, vestibule); after; since

to be separated; to be apart; to be distant; to leave; to go away; to leave (a job, etc.); to quit; to give up; to lose connection with; to drift away from