normal feelings or could I be overthinking

I have recently found out my s/o is not being completely faithful and/or honest. My first instinct was to ask if he ever felt like I was cheating or dishonest. Partially because he recently said I was being weird with my phone and saw heart emojis ( I send to my mom, girlfriends, sister etc) and I know that could’ve given the wrong idea. I have never cheated though and I wonder if he felt like I have so that made him do what he did.