'Tis better to have loved and lost
Than never to have loved at all.
- Alfred Lord Tennyson

Such is the problem of immortals, that other lives seem like fleeting moments. But that doesn't make their lives any less special.

Despite everything, I still picked "I have places to be". Although there is no confirmation that Frisk has a family on the surface, lore from tortoise shopkeep suggests Toriel is immortal and stuck at her current age unless she can bear another child.

So unless you can get Toriel and Asgore to hook up together again (highly unlikely) you will inevitably make them go through the pain of losing their child yet a third time.