How would you feel?

I have had a on and off relationship with my sons dad for almost 6 years now 🤦🏻‍♀️ .. little did I know at the time he was a drug addict (meth) .. I helped him get clean and shortly after I became pregnant . Fast forward .. july of this year he came out of a rehab center where he was for 4 months , we reconciled and recently we moved to Mexico .. the other day he was acting really shady about his phone . Then later tells me he was “talking sh*t” about me to a coworker and then later changed it to “I was asking for advice”. (A coworker I’ve never met or ever heard on the phone) said coworker told him to come over and spend the night .. Hummmm right ?? Then today I decided to look through the phone and saw he was trying to download Textnow app .. when asked he beat around the bush til finally he says “I was planning “ then later said “planning on playing you” (cheating) .I have helped him get clean , even when on drugs have always helped him , been to all his family events for my son to be present , and never denied him his son , was there for funerals to take picture for him while he was in rehab I’ve worked 2 jobs and still found time to drive to Mexico to visit him for his rehab events and I’m feeling like this is the thanks I get . I’m salty .. it took me everything not to put laxative in his lunch today ..