いつまでも
いつまでも · itsumademo · JLPT N3 · adverb
forever
⏳ itsu (when) + made (until) + mo (even/any) = until whenever → forever
いつ means when, まで means until, and も turns a question word into an 'any' word. Put together it means until any time at all, with no end point, so it means forever. Compare いつも (always): add まで and it becomes 'always, with no end'.