[Terms like, 'you belong to me' are metaphorical in nature. They do not indicate that a person thinks his/her spouse is personal property. Personal property can be bought, sold, bartered, etc. That is not what those metaphorical romanticisms mean. If they meant that to you and islam, then someone should come out in droves and try to fix it before your women rise up and strike you down. And in the modern world that is quite likely.
BTW: What is she doing now? Giving you a foot massage?
They are metaphorical in Sunni's case, as well. His wife can't be bought, bartered or sold, though she could choose to leave and/or give herself to someone else. Thus, she isn't actually property.
FWIW, I am a huge stickler about fidelity. My ex was a chronic cheater, and I wouldn't tolerate it in my current guy. His body (sexually speaking) belongs to me, and mine belongs to him. I consider his sexuality my property, as mine is his. Were he to share what belongs to me with someone else, it would end our relationship, as I think it would for most of you.