She wants to be that girl

One of the girls I'm going out with seems to be thinking it's time to take our relationship to the next level, only problem is that she is married and has kids. Our situation it's a cliche, her husband is an asshole, don't work, don't gives he time etc. and I'm the shining knight that gives her full attention. But yet 2 years ago I was that guy, with exception that I have always worked. I know she would probably leave her whole life behind her including her kids if I ask her to, I like her we click, the chemistry is there and could really grow to love her, but I'm hesitant to be in a long term relationship ever again, eventually because of my personality and job she will eventually leave as well probably with another me, telling him that I'm an asshole etc, etc. Although my empty apartment reminds me every night that loneliness is my only companion, and about the emptiness in my life, for some reason  I am not unhappy.