It's not about how's okay to groom a child because in the future she'd become your wife and the time gap will shrink. The scenes with older, wiser Henry caring for child Clare (with her absent family) is a literary device to show how that internalized child receives support and gets well due to moments of care from her partner. Due to the fantastic device of time travel, it's not a psychological metaphor for growth, but the “inner child” becomes an actual younger version of self. Which is weird because it's not an adult reexamining her history with new experiences.

There's a cool idea that younger “asshole” Henry cuts his hair for her, to be that older version of self. Which is complemented by her disillusion with the old memories.

The friends are weird. The woman has no influence on the plot (and it's weird Claire didn't tell at least something about her Henry). The man at least has some advancement.