Why do most mothers get heartbroken when their kids grow up?

My mom has always been sad and cried on our birthday because we're getting older. My cousin who has three kids who are 12, 10 and 8 shared a photo from 2013 when they were 7, 5 and 3 and she was like, "OMG They were so little!😭"
Another woman said, "Why do tbey have to grow up?!!!" Then my cousin said, "I know. It's so heartbreaking. I wish they would stay babies!"
My mom said, "Kids grow up so fast. How do you think I feel with 20 something year old adult kids?! I'm a lot more heartbroken. Enjoy your kids being kids because you will miss them being little. My husband says he don't miss his kids being little but I think he does deep down lol."
My dad doesn't really miss us being little.

Keepitsimple · 51-55, F

Because our kids become our life. Everything we do is for them and about them. We’re their biggest fans. When they are gone a piece of us leaves.

daveal · 56-60, M

@IAmBianca96 parents can be both sad and happy to see their children grow and mature. Give it a decade and a couple of kids and you will understand.

Keepitsimple · 51-55, F

My kids, your age and older see it different. We had great times traveling to their games and competitions and races. We enjoyed doing things together. Yes, they grow up and start their own lives and we are happy but it was still one of the best times in our lives. @IAmBianca96