Number One held his women for a short moment and finally realized how lonely his past self was. He had no one to share his success or failure with and couldn't reach out for advice or share his experience. He was all to himself and it would have continued like this if Nami didn't appear in his life.
It didn't really matter that Nami was led to Number One as a challenge. She wasn't forced to bond with him and decided to pursue him on her own accord. He was able to open up thanks to her and finally share his happiness with others.
"Mhmm…" Nami murmured as Number One caressed her cheek and questioned in his mind while rubbing her nose against his neck. 'Did you succeed? We took turns looking after you but I fell asleep...'
'It's okay, I thought it would take me less time but I made some discovery and began experimenting,' Number One explained as he gazed at Luna and carefully lifted both of them. 'I will tell you both the details when Luna wakes up.'