i think he may be cheating on me?..

He's in the military and we hangout every weekend day thru 2am and also hangout on Monday Tues and Fridays. He isn't on his phone when we hangout and even if he does he use it Infront of me. When I was in the car and he checked his phone I saw a heart next to the name so I am confused.. and I believe he sent this to me by accident?