To me physical abuse IS sexual infidelity. Instead of having sex with their wife, the abusive husband is beating them up!
The Fuller Theological Center states this almost exactly:
"Physical abuse constitutes a kind of porneia, in fact, because it is direct and sinful bodily unfaithfulness. It is just as much a violation of Ephesians 5 marital nurture as having sex with someone outside the relationship. It is a destruction of one's body and dignity, and thus a destruction of the vow to protect, cherish, and nurture."
She has the right to divorce AND remarry a real believer who won't break that vow.

The Fuller Theological Center states this almost exactly:
"Physical abuse constitutes a kind of porneia, in fact, because it is direct and sinful bodily unfaithfulness. It is just as much a violation of Ephesians 5 marital nurture as having sex with someone outside the relationship. It is a destruction of one's body and dignity, and thus a destruction of the vow to protect, cherish, and nurture."
She has the right to divorce AND remarry a real believer who won't break that vow.