My dad's cheating (long kinda)

So back story. My step mom and dad haven't always had the best of a relationship but they still stay with each other. They fight a lot but I am close with my step mom and I know she still cares. Well this weekend my dad is supposed to be going to training,for his work. Well his phone was ringing and I picked it up to see who it was because he was in the shower and it had a weird name well I didn't answer and I waited until it stopped ringing and the person sent a text saying well since you won't answer I love you. I opened it and started reading and found out my dad is not going to training he's going to see her and he's cheating and I honestly feel bad. I love my step mom... I don't know I needed to share.