Worried im stressing out baby

A few hours ago I found out my SO cheated on me a few months ago. He told me because he knows he wants to be with me forever and didn't feel he could move forward without me knowing. I feel everything has been flipped upside down. Been a very stressful / emotional few hours and I'm having serious trouble making myself feel better, how can I ease the stress on the baby I'm really scared of how this is effecting her I hate that she feels my stress I just want to rock her in my arms. What can I do Im devastated but I've been trying to lay here and talk to my bump telling trying to calm us down (I'm 17 weeks) I don't want my pain to be baby's pain :(