Seems to me that if a woman bears 100% of the responsibility for the choice to have an abortion, she should bear 100% of the burden for the consequences of having the child. A father, therefore, should be able to opt out of paying child support.
100% her decision, 100% her financial burden.
Fair is fair.
Fair, except for to the child.
Your proposal doesn’t assure fathers of the right to not have their child killed.