love life vs sex activity

love life and sex activity both are nouns.

Word	Noun	Adjective	Verb	Adverb
love life	Yes	No	No	No
sex activity	Yes	No	No	No

As nouns, sex activity is a hypernym of love life; that is, sex activity is a word with a broader meaning than love life:

love life: sexual activities (often including sexual intercourse) between two people
sex activity: activities associated with sexual intercourse

Other hypernyms of love life include sex, sexual activity, sexual practice.

love life (noun)	sex activity (noun)
sexual activities (often including sexual intercourse) between two people	activities associated with sexual intercourse