Is any abuse acceptable?
No, however common sense should prevail.
I know a guy who was reported (& arrested) for domestic violence after flicking his partner with a pair of pajamas. This manipulation of hard won protection laws does sadly happen, but not often. The bigger problem by far is the under reporting of abuse.
How long does it take normally before a victim realises her man is abusive?
In my case, some signs after 6 months, then massive escalation after marriage. Mr X is one of many abusers who regard marriage as ownership. Other abusers may have different milestones. Nearly all believe they own their victim.