sexting

is sexting considered cheating? and would you stay with your SO?
2 weeks ago I found out that my boyfriend sext another girl and once I saw it on his phone my heart literally felt like it was ripped out of my chest. I felt betrayed because it took me a very long time to show him my intimate side and feel comfortable with it and once I saw that they were talking like us it just made me feel horrible. my sex drive is now gone.