I can't wrap my head around how mothers leave their kids to do drugs and party .I did party every…

I can't wrap my head around how mothers leave their kids to do drugs and party .I did party every weekend and I did do very stupid stuff , I did try drugs , I did drugs when my dad passed away when I was 16 , my "friends" would be right behide me telling me to do it .if I didn't get with my boyfriend soon after turning 18 it's hard to tell where I would be to be honest I haven't touched anything even before I found out I was pregnant all I done was smoke cigs and as soon as I found out I was pregnant I stopped smoking but now having a child I could NEVER go back to that life . my dad done drugs my whole life he od when I was 14 he was in the hospital for 2 years getting open heart surgerys I watched my dad die. I could never imagine putting my son through that.. I just don't understand how someone could do that to a kid.