Every pro choice person I've ever come across is in favour of good sex education and access to good, free contraception.
But - sometimes education and contraception fail. Sometimes there's no consent. Sometimes circumstances change after conception. Sometimes the foetus has abnormalities. Sometimes the woman's health is at risk. Sometimes the foetus is just straight up unwanted.
For those cases, we all need access to abortion.
Absolutely no one wants an unwanted pregnancy in the first place. No one thinks abortion is desirable - just that sometimes it's the least bad option.
I personally know one woman who died in childbirth, and two who were permanently disabled by childbirth - one of whom died prematurely 30 years later as a result, and the other of whom is unlikely to ever be able to return to work, or even drive.
In case you're thinking these cases are from a long time ago, they're not. They're from 1 year (permanent disability), 9 years (death) and 30 years ago (permanent disability and premature death).
Let's not pretend that pregnancy and childbirth is some sort of risk free paradise.