Why are some women so attracted to men that are in relationships/married and are willing to be the side chick?

It's not just for the clichéd "forbidden fruit", but also because a married man is generally - or at least perceived as - successful and overall desiderable, both biologically and socially.
For some women, this factor is further enhanced if said man has had children too - basically they perceive him as so confident, successful and desiderable that not only he got to marry a woman, but also had her carry his children, which means he's reliable, trustworthy and a great provider.
So for some women (not all obviously) this clicks as something they must have.
This is something I had the chance to see with a female acquaintance of mine - she didn't talk much to me, then I got married and she suddenly started to text me and randomly comment on Facebook. I had my first child, and she got more insistent. I remember thinking: "How nice that she's so interested!" while my wife just said "Nah, she just wants to get in your pants". When she started to PM me and suggest we could meet for a beer - not me and my wife with her, just me and her - I made excuses until she gave up.
same as a lot of men, like to have a married woman, have their fun and not have to see them until the next time,
Opinion
9Opinion
Female hypergamy, many women want only the top men, and those are likely to be token.
Maybe they are insecure n want to mess up other people's relationships could be lots of reasons
Trauma responses coupled with evolution. Females are wired to find a mate that can support a family and has characteristics of a good father.
They want what can't have, but desire what they can kinda collect. Homewreckers typically hunt broken marriages/relationships that were totally gonna end anyway.
I would rather be the side chick than be married
Why?
I have no idea, but I'm considering wearing a ring!
No self respect is what I think it comes down to.
I assume self esteem problems
They love being a whore don't know why
Exactly n want the money
Daddy issues
It can't be just that.
It's fun
Superb Opinion