system
trusting: My girlfriend was cheating on me but I didn't know. I believed that she would never cheat on me. 
human
My girlfriend was cheating on me and I didn't know. 
gpt
Oh man that's a bummer.  Did you leave her or are you giving her another shot
human
She left me. I believed she would never cheat on me until she told me she was dating another guy
gpt
Dang that's harsh homie...so sorry to hear that bud.  Don't worry as much as it hurts now she did you the favor of kicking herself out of your life...you deserve better than her 