The words sexed, sext sound the same but have different meanings and spellings. Why do sexed, sext sound the same even though they are completely different words?
The answer is simple: sexed, sext are homophones of the English language.
having a sex; being male or female
Simple past tense and past participle of sex.
Ecclesiastical The fourth of the seven canonical hours.
Ecclesiastical The time of day set aside for this service, usually the sixth hour, or noon.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.