'-(으)니' in Seung Ki Lee's song '지금부터 사랑해'

Question today comes from Tan in Malaysia.

I'm now trying to understand the song "지금부터 사랑해" by 이승기,
and of course.. I'm facing some problems. :( Please help!!!

"지금 와서 보니 추억도 많더라"

- I'm eager to know how to use "보니", I know "보다" means "to see", but I wonder its usage right here means:

→"looking back"??? as there is an "오다" [back] before it... OR,

→ the "보니" is actually a grammar point which indicates "After doing..., I found out that...", or only the "-니" is having this indication, not the whole "보니"?

Many thanks!