I hardly ever post, and I've name changed for this. I just wanted to give you my experience.
My dad had an affair that lasted 2 years starting when I was 8 years old and my sister was 6. His AP was also married with two kids of a similar age. After 2 years of the affair my dad did in fact leave my mum. Over 25 years later my dad and his AP are still together and now married. He has now been with his AP longer than he was ever with my mum. So in this instance, yes. The affair 'worked'. However. The fallout from the affair was massive, and still ongoing.
My sister is almost completely no contact with my dad. She has never forgiven him, and has ongoing trust issues around men. They speak sporadically on special occasions. I have ongoing mental health issues and feelings of abandonment and anxiety, which I have been in and out of therapy for since I was a child. I love my dad, but do I respect him? Feel daughterly towards him? Honestly, not really. He's like a friendly uncle. My mum developed an eating disorder from the stress of the affair and divorce, which, although she is happily remarried, she still struggles with. We lost our family home, although we were never homeless, which has lead to both me and my sister living in some very risky housing situations as teens and young adults. My sister and I both had to pick a parent to attend our graduations and weddings. We became estranged from our dad's side of the family. His parents, my grandparents, disowned him. They died without being reconciled.
AP's eldest child went to live with her grandparents when my dad moved in to her family home, and changed her surname so it no longer matched her mum. Their relationship is still strained and uncomfortable.
My dad has told me before that he feels guilty every day for what he did, and blames himself. He cries sometimes. His AP suffers terribly from anxiety and suicidal ideation.
OP. Is this what you want from your future? Families do not just 'get on with it' after an affair breaks them apart. They suffer, sometimes forever.