Guess you never fought anyone or much? It settles alot of disagreements. Two people have a disagreement and fight it out. Whoever wins or gets the better of the other feels satisfied and the other leaves it alone because they don't want to fight anymore. They move on (most of the time). 

Being hit by another person is okay? If things are getting this bad, your relationship is in big trouble...

Not in "other person"-defense?

So your avy will soon be a faithful representation of your actual face ?

Personally I've grown up in a family where adults didn't have scruples teaching stuff the hard way to kids and while I'd argue some of the actions of my parents I still think that moderate violence is key for education. Learning martial arts I only apply violence when I see someone else trying to phisically harm me or someone weaker thant them. I don't think sex should be considered when talking about hitting other people, of course it's more likely that a woman gets hit by a stronger man, but there's also the possibility of a strong woman hitting a weak man, in which case I wouldn't waste time thinking if it's right or not to hit a woman and I'd simply help the weak man. It's just a matter of who's the weak person and does he/she deserve to be hit.

Within reason also in other persons defense. If someone is unable to defend themselves and violence is your last resort to diffusing the situation then yeah.

I'm obviously not saying if you see, for example, someone being raped you should just walk away and not help them, etc...

While spurges private life seems to be a tad chaotic right now, I assume we are dealing with adults here (although his girlfriend honestly doesn't sound very mature..:P) and according to him, this was an honest mistake so it still shouldn't be a big deal at all.

Or am I missing something here?

Doesn't his son have a phone?

Well, I dont know, but sometimes they dont.I personally only got my first phone at age 15.

But most importantly, as a parent you would want all contacts you can have to maximize the safety of your child.What if the battery of your son phone ended?Or if he lost the phone?Or he is so entertained with his friend and dosent pick the phone, when you have something important to say?Having the mother number would just be a backup plan.

Plus, why is such a big deal having the number?Not every relation betwenn man and woman has to be sexual, you know

well i think most of us jokingly are say it wasn't a mistake but intentional since he been denied at home lol. 

In a bondage session?