Do I have to feel bad about cheating on my pregnant wife even though her past is just as dirty as mine?

I've been with my wife for 8 years(3 years of dating, 5 years of marriage). We have a 2 year old daughter together and she's currently 7 months pregnant with a boy. I am having an affair with two different women and I know it makes me seem like a loser but the reality is, my wife is a tramp. Sure, I love her, she loves me and she's never been unfaithful to me but her history really tears me up for deep personal reasons. My wife has a 10 year old son(my stepson). Her son's father is a married man who betrayed his wife when he had with another woman and impregnated her. I tried to look past my wife's history being that this happened before she met me. But I can't help it. I NEVER forgave my father for cheating on my mother and leaving her for his . My dad left me, my mom and my 3 siblings struggling, poor and broke. Therefore, if my wife finds out about my cheating, I hope she'd be willing to work this out. Did she give a damn about her son's father's wife's feelings when she was screwing him? I have no respect for homewreckers. I don't respect the who stole my dad, I don't respect the s I'm sleeping with and sadly, I BARELY respect my wife. But rest ured, I DO love her, otherwise we wouldn't be married. Am I wrong or do you understand what I'm feeling?