Found out truth about why dad left I feel horrible

I have no one to talk to so I’m venting here this is a long read I apologize I just found out the truth about why my dad left… and I feel horrible I’m 27 and I have a younger sister. For years, I resented my dad and even hated him at times. Back in 2015–2016, he left for about three months without any explanation. During that time, my mom took her frustration out on us. My sister seemed to get it worse, and I always felt like it was because she looks more like him. Growing up, I saw my dad as weak—like someone who let people walk all over him. My mom would say a lot of negative things about him in front of us, and I’ll be honest, I agreed sometimes. Meanwhile, my dad never spoke badly about her, never explained why he left, and stayed quiet about everything. Even up until my sister’s graduation, they barely spoke. He would Uber us back and forth instead of interacting with her directly, and if they did communicate, it was mostly through text. Recently, I was going through some of his old things and found old phones. I powered them on and read messages that completely changed everything. I found texts of my mom begging him for forgiveness after cheating on him. In those same messages, he said he was leaving to get his life together and figure things out. Now I feel like my whole perspective was wrong. I judged my dad harshly without knowing the truth, and I treated him in ways I deeply regret. I don’t really know how to process this or what to do next, but I needed to get it off my chest.