Feeling betrayed in my relationship

Hey all. I'm new here and just need to turn to others who are or who have dealt with what I'm going thru with my spouse. You know when you get that gut feeling that you just can't ignore? I had this issue this week. Long story short but my husband doesn't get along with his ex wife and they share a son together. When he would text her, they both would get off Subject of their son and talk about the past and he would ALWAYS tell how much he wished she didn't hate him and how he wishes her all the happiness in the world. Go back a year ago, I had this same feeling and so I went thru his phone (just to hurt my own feelings) he was telling her how much he missed her and how unhappy he was with me. Ok so back to them texting, i started doing all the texting for him off his phone cause he was tired of me being upset and us always fighting over their conversations. This past week he asked me to text her and see if she would bring their son to my daughters birthday party, told him absolutely not cause it's not gonna happen. I sent her a message anyways, of course she said no. I told him I wasn't texting her back, he yelled at me infront of our customers and my father in law, saying everything was my fault. Anyways I had a weird feeling that he was texting her again. My nosey self went thru his trash and sure enough he deletes some of their messages he didn't want me to see along with another girl he gave his number too. My feelings are so hurt and he says I'm out of line for having feelings and being upset. It throws me into a deep depression ? feel betrayed and so beside myself.