彼は愚かにもあんな間違いを犯してしまった。

he; him; his; boyfriend

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

foolish; stupid

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

too; also; in addition; as well; (not) either (in a negative sentence); both A and B; A as well as B; neither A nor B (in a negative sentence); even; as much as; as many as; as far as; as long as; no less than; no fewer than; even if; even though; although; in spite of; further; more; again; another; the other

such (about something or someone distant from both speaker and listener, or about a situation unfamiliar to both speaker and listener); so; that; sort of

mistake; error; blunder; accident; mishap; trouble; improper conduct (e.g. between man and woman); indiscretion

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to commit (e.g. crime); to perpetrate; to make (e.g. mistake); to break (e.g. rule); to violate; to transgress; to contravene; to rape; to violate; to ravish; to deflower