I feel sorry for OW. I think they're mostly vulnerable and damaged to fuckery. Anyone with an ounce of self-esteem and joy in their lives wouldn't do that to another person.
This is wishful thinking and projecting. You would never do the same being a nice person, and therefore imagine other reasonable women will not. Especially happy women. But you are wrong.
Happy, smart, attractive, independent women knowingly become OW everyday. Some prefer it. Just think, a married man with kids is often quite a catch. He is responsible, usually well groomed due to being looked after, is more knowledgeable about women due to living with one day in day out and dealing with the emotional ups and downs. Is good with children due to DCs, is patient and more mature.
For some women, that's pretty attractive. And for men DCs seem to boost their worth, whereas for women they are seen as a negative. I have met men at functions etc (not knowing they are married) and thought 'wow this guys got something going on', and that 'something' in large part often comes down to him being married with all the experience and growth that comes with that.
From that perspective OW are really seeking to take everything that another woman has worked hard to build. Some just have no scruples about doing that.