I'm seeing the same pattern here as elsewhere... blame her for his actions by claiming (without evidence) that she "stole" the phone, or "grabbed" the phone, or other assumptions that put the blame on her for his aggressive behavior.
So let's play some more "what if".
What if he wanted her to hold the phone, as many men do want their wives to hold the phone in her purse?
What if the phone was sitting on the bench, and she picked it up?
Any of these "what ifs" are nonsense because no matter what the prior circumstances, assault and battery is NOT an appropriate way to regain possession of a cell phone from your spouse.
I don't think it's really that complicated:
Person A has Person B's phone and won't give it back: that amount of force seems reasonable from Person B to take it back
Person A has Person A's phone: no amount of force is reasonable from Person B to take it.
Dragging words like "spouse" and gender into it are irrelevant. We should not try to assess the dynamics of someone else's marriage. Nor should we presume special treatment based on gender. We should treat them as individuals with their own moral agency.
First of all, I assigned ZERO "special treatment" to anyone because of their gender. Your incorrect assumptions otherwise lead to your inability to see this situation clearly, in my opinion.
Second, the fact that these two people are married to each other (or otherwise have an ongoing relationship with each other) DOES matter. Far too many people seem to be trying to portray her like some mugger in the street, and are making unsubstantiated assumptions that she "stole" his phone as if this somehow justifies his assault and battery.
It doesn't.
And it wouldn't if the genders here had been reversed, either.