I am I overreacting

My boyfriend of two years cheated on me when I was pregnant and I forgave him but that 6 months ago , yesterday he was texting his so called *girl* friend from high school and they been talking since 7 am until 10 pm and she posted a binki pic on her Facebook story and he replied Gorgeous and I went through his phone last night when he was in the shower and he text her saying I dream about doing you in the butt jk Personally I don't have that funny

Also I don't have a problem with him giving Compliments to other girls but just what text message