No appropriate title

I had a problem finding a title for this post. feel so angry and frustrated and mad at a man, unfortunately someone I know well.
I met his "first" wife at a special occasion few days ago, and by end of our evening together I found myself wishing to see him to tell him exactely what i think of him- nothing positive or good at all.

She is a beautiful, elegant, very well educated lady, at her mid 40s, decending from one of Egypt's best families, has her own inheritence, active member at some NGO's, mother of 3 beautiful and very well raised kids: daughter and 2 sons.

She looked so sad during the whole evening, but was bravely trying to hide it. yet her beautiful eyes showed this deeply rooted sadness.
I approached her talking about different topics, just general issues- when she accidently told me that her husband is staying "at the other house" tonight. its thursday, you know......

for few seconds i wasn't able to say anything, i simply found nothing to say to comfort her.
she looked hurt and sad. very deep.
I thought oh God, her wound didnt heal yet. she is still hurt from his betrayel, when he years ago married his secretary behind her back and kept on decieving her for years....
I guess such wound would never heal.
I wanted to hug her and apologize for being his relative. I literally felt guilty, I dont know why.
maybe because i dont want to be realted to someone as cruel as he is?
or maybe because i can not "punish" him for what he did to her?

Why the hell would he need to secretely marry another woman? what is he missing in his wife? why didnt he tell her before he marries that other woman? why was he a coward to do it behind her back all those years, until it was "fact of life" and she had to accept it in this humiliating way?

I am not discussing the concept of having more than one wife, which is one of solid rules/concepts of Islam, nor am I condemning him for his second marriage.
All I am saying here is THIS way is badly hurting an innocent person- in this case his first wife- who has every right to be fully aware of all arrangements, legally and officially informed of the second marriage and approving in written.
In this case here, the incident was completely different. it was a secret marriage, big sum of money paid to the other woman (!!!), everything taking place in complete darkness for years, until it became a fact of their life, which his wife HAS to accept and deal with.

isnt this process more like a robery or smuggling or illeagal doing?
isnt it unfair towards a woman, who did nothing but trusted her husband enough not to humilate her this way?
isnt it a shaking incident for anyone's life?
Isn't this clear betrayel to someone's trust?
how would I ever trust someone not to hurt me this way, after years of settling down and having a stable family?
I can not forget that sad look in her eyes, and can not find any proper excuse for hurting her this way.
All i can feel here is stab in my back. does anyone deserves to be treated like that?
why? for just being a woman?

Is it a man's right to treat his wife this way, just because he is a man?
this is not Islam, what is it then? traditions? culture? human nature? weakness?
pure male nature?

I dont want to be a woman, I want to be a man.