Relationship problem

I found out a few months ago my boyfriend had downloaded & deleted tinder. I've been with him nearly 8 yrs & we have 2 kids. My question is... how do i ask him why he had it & if he has an account etc.? Tia

*I found out by looking through his app library*

*I endeded up just asking after a blow out & he said he has no idea how it got on his phone! I don't know whether to believe it or not 😂. He said I clearly don't know him & does he honestly think after all this time he'd go out shagging other women?! I responded by saying you could have just spoken to them! That's enough for me! He literally laughed in my face. So I don't know if that was him being defensive*