The harm is to the children psychologically for one. Children need a proper mother and father. I don't know of any child that would be happy with their mother or father sleeping around. Secondly, when he finds his best piece of a%% he wont want to be around the "ones he loves".
Love is not all gushy-gushy warm kisses. Love is sometimes a sacrifice of doing things you don't want to do but you do it anyway because you truly have love in your heart.
Additionally, why doesn't she have any interest? The two need to talk. Bringing home disease or having a pregnant mistress or some other screwed up consequence isn't going really be OK with anyone that I know of.
There are truly absolute rights and wrongs in this world even if some "seem" to be unaffected by living outside of moral boundaries.
Well and truly stated.
If works for some and the families stay intact. With a mother and father. One size fits all doesn’t work with all families.