Altho it’s allowed I’d find it worse having to come face to face with the woman he’s sleeping with. I would prob slap her, call her a wh*re then tell her she’s welcome to him. I would** never** share my husband with another woman. I understand second wives don’t always know hubby was already married but if she doesn’t seem shocked by the sight of me (and possibly my kiddies) it’s a safe bet it doesn’t bother her. Out of all the millions of single men in the world why latch onto someone who is taken. Husband would get a slap as well 
I wouldn’t fight for him, if he doesn’t love me imo I can’t make him and I would rather he divorced me than lay there at night thinking of her, comparing everything I do with the way she does things etc., staying with me out of some sense of ‘duty’ or pity. Stringing me along and lying to me whilst he sleeps/intends to sleep with another woman is humiliating and something I couldn’t forgive.