I think my boyfriend is cheating on me, please help

I need so much advice. First of all, my boyfriend and I have been together almost 5 years, in 2 weeks it’ll be 5. We just recently got an apartment together after living with his parents for 2 years. I just want to say that I trust my boyfriend more than anyone, we fight but we get past it. We trust each other. We’ve gotten better at communicating and knowing when to sit down and just talk. Last night after he went to sleep, I just couldn’t calm down and fall asleep. I decided to look at his phone, which I never do unless it’s important. I found out he downloaded tiktok, no big deal but he liked a video of a girl showing off her butt and that’s the only video he liked. & he’s been searching for girls who are only known for their onlyfans accounts. I go on his snapchat, mind you I’m not even his friend on there BUT a girl with the exact same name as mine is added and they have recently snapped. They’ve deleted the conversation and I decided to be desperate and add her on my snapchat to see what is happening… Do i message her and ask? someone please tell me what to do. We’ve had this conversation before and I just can’t do it. I want to fix whatever is going on even if it isn’t my fault. I will be so heartbroken if he is cheating. Just please help a girl out that’s all i ask

You can always message her and tell her your the girlfriend. Hopefully she’s the kind of girl that will back you up and be your friend, but you do have to also know she can be the total opposite. If you do message her, don’t go at her all crazy theres a big change she isn’t aware. Tell her your the girlfriend, ask how long it’s been happening, and what has been happening. If you don’t decide to message her, I would ask him. That’s tricky because you were looking on his phone so he can use that against you ya know. But obviously something is going on and you need to figure it out.