The writer later claimed that his script didn't call for Pym intentionally hitting Janet, just flailing around and doing it by accident. He blamed the penciler for going overboard.
That's his story, anyhow, but it was Jim Shooter, so I am dubious. Some of us remember the misogyny he demonstrated elsewhere, including the character of Madelyne "Debbie the Duck" Felix.
Anyhow, this is why I'd have gone for Lang. Ex-con, yes, but a doting father and not a wife-beater. Just saying...