Wanting a man’s perspective

I’m gonna keep this short because it’s just too much to write and quite frankly my brain is really frazzled and I can’t think straight, I have my suspicions that he’s cheated somehow at work, his little firm has no women working there but sometimes they’re contracted to a factory where there is women, and he has said to me “if I could cheat it would be at this factory”, yeah I know, he’s fucking stupid, but I think he might have just meant that that’s the only place there’s women when he’s working, I can’t find anything at all on his phone, all of his work colleagues are close friends so they’re not going to tell me anything, I’ve tried messaging women that work in that factory that I can find on Facebook, I have no proof he’s cheated I just have a hunch, he has been rejecting sex for about a year now and when I asked he told me he’s been watching porn and pleasing himself instead, his reasons being we weren’t in a good place and I weren’t talking to him very nicely apparently, and also silly things he said like he could cheat at this factory and what not has made me think, has he cheated? We have a 3 year old and a 2 month old, we’ve been together 6 years, I’d be devastated if he has and I just need to know, how can I find out if there’s nothing on his phone and he’s not going to confess, it’s not really possible to spy at work because it’s a factory you can’t just walk in Willy nilly, anyone got any ideas? I’ve asked him and I feel like he is lying