彼はすぐに疲れた。

he; him; his; boyfriend

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

immediately; at once; directly; soon; before long; shortly; easily; without difficulty; right (near); nearby; just (handy)

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to get tired; to tire; to be worn out (e.g. of well used objects); to starve