Songfacts®:

• A piano-heavy ballad, "Lost On You" finds Lewis Capaldi accepting that he's not able to carry on with his lover. He tells her despite their best efforts, the relationship is bleeding him dry.
  
  You know that I adore you
  Though I couldn't give enough
  Hope you'll be safe in the arms of another
  'Cause I can't take the weight of your love
  
  It is likely Capaldi is referencing the same split with a long-term girlfriend that he sings about on "Bruises." That breakup was amicable.
• Capaldi told Genius regarding "Lost on You": "It's not an easy thing to do but sometimes it's better to let someone go off and be happy with someone else when things are falling apart. But at the end of the day it'd be selfish to hold someone back from being happy because you don't want anyone else to be with them but you. In my situation we both knew that at the time we couldn't give the other person the time or attention they needed or deserved due to some stuff out of our control - so we had to end things."