彼はもう行ってしまった。

he; him; his; boyfriend

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

now; soon; shortly; before long; presently; already; yet; by now; (not) anymore; further; more; again; another; the other; interjection used to strengthen expression of an emotion (often exasperation)

to go; to move (in a direction or towards a specific location); to head (towards); to be transported (towards); to reach; to proceed; to take place; to pass through; to come and go; to walk; to die; to pass away; to do (in a specific way); to stream; to flow; to continue; to have an orgasm; to come; to cum; to trip; to get high; to have a drug-induced hallucination