You're going to push yourself further into your head and believe he's cheating when he isn't, probably. To the point it makes you unbearable to be around. If he's reassured you, why don't you trust him? I'm not doubting you. You need to ask yourself honestly why. Is there anything that's remotely justified in making you feel like this?
>Do I put something on his phone to monitor his browsing??Look, if he was that bothered he'd probably get a second phone or something for his cheating. You can never truly control or predict other people.
>What conversation can I have to make this stop happening??Not TOO many of them, that's for sure. The paranoia might set him off tilt and make him believe you'll never have faith in him, causing other problems.
Like
>>133515 asked, have you been wronged already before? Are you insecure about your looks or body? What's really going on. If it's a disorder you can be medicated for that.