<human>: I've just right now found out my dad has cheated on my step mum with another woman whom I have never met.
Infidelity was also the reason behind his divorce with my Mum (they were together for 18 years).

Other than the obvious shitty situation this puts my step mum in, it's put me in an awkward one too. Being 20 years old, I've been looking to move out recently, but have decided to stay home just to save money, and I just couldn't afford it. I love my step mum, she really is a great woman and has never crossed the line in terms of trying to raise me, but has also provided me with all the support I've needed. I have a great relationship with both her and my biological mother.

But what do I do now? I don't blame her for wanting to get rid of my asshole of a father, he cheated on my mum and I could never regain any real respect for him as a father, or even a man. But now he's gone and fucked up another relationship. He was even married briefly in his early 20's to another woman.
But there obviously isn't going to be any custody battles with me, I can't move in with my mum, living arrangements wouldn't allow it (not that I wouldn't love to), I can't really expect my step mum (soon to be former?) to keep me around. And fuck my dad, seriously. I don't want to see that man's face again.

I don't really know the point of this post I guess I just needed to say something, or vent somewhere.
This whole situation brings up the feelings a 14 year old me felt when I found out he had cheated on my mum. It gave me a horrible empty feeling, that I'm feeling as I type this 
Obviously it's a different situation, I'm older and it's with my step mother rather than my actual Mother.
But how could my father continually do this to good women?

Can you condense the text into three sentences or less?
<bot>: Father cheated on Step Mum, had previously done the same with my Mum. Not really any questions, just need a vent.