I'm a little 'torn' though I definitely agree he should have watched it, especially since they are married and her purse is essentially his. But maybe he was not paying attention since he was on the phone, and maybe she assumed
he would watch it though she knew he was on the phone and probably wasn't giving his undivided attention to her. If he wasn't on the phone I bet he would have been more aware that her purse was left alone and wouldn't have lost sight of it (or maybe not, I don't really know)
If she trusted him to watch it and he HAS watched it before, then it was an honest simple mistake. She wouldn't really have to ask if he always watches it.
BUT - if she knew she couldn't trust him, then she should carry her own purse, or ask, since it is first and foremost her purse, and she should be more careful. I don't think people should leave valuables around and assume
someone else will take responsibility. That'* NOT to say he should have left it just because she didn't ask him to watch it. He should have watched it, but all I am saying is that maybe she should also be more careful herself.
I would always watch a purse regardless. It doesn't bother me either. Some drunk idiot at a bar pulled a chair out from under me, sending my g/f'* (ex'*) purse flying open on the floor (it was on the chair behind me). The first thing I did was pick up the purse and all the stuff that flew out of it. But that'* just how I am.