TIFU by going through my boyfriends phone.

Let me just start this off with saying i’m not that type of girlfriend. i’ve never felt the need to go through anyones phone i’ve always been trusting that my boyfriend will know his boundaries and if he crosses them then it’s kind of game over, he’s a grown man he knows right from wrong. Anyways, recently we haven’t been doing the deed often at all maybe once or twice a month, we are both in our 20s and i’m aware i have a higher drive than he does but i feel like a married old couple. we come home from work, eat then sleep that’s it. So this was playing on my mind a lot and i expressed to my partner about the lack of activity between us and he said his same old excuses that he always says when he doesn’t want to, he’s tired, his back hurts, he’s just not in the mood etc etc. but for some reason i just wasn’t happy with this answer i just had a feeling, probably insecurity - his constant rejections just made me feel like he doesn’t find me attractive anymore because ive gained a little weight or the honeymoon phase has worn off. So being a typical insecure female my mind instantly went to the conclusion he must be interested in someone else, whether he’s actually meeting up with them when i’m at work or if he’s messaging them etc but i just had to find out. so i went through his phone after he fell asleep, at first i found nothing, not even a message to a female friend he doesn’t like anyone else’s photos or anything! so i felt really stupid but at the last second i opened the browser, and was met with pages upon pages of prn. Weird stuff too, things like “she male” and pgging. i was in shock. the man who on countless occasions has turned me down because he’s not in the mood because of his famously low s*x drive is actually very active when i’m away. the shock overtook me a little bit and i got upset thinking this was confirmation that he no longer finds me attractive and he has to watch this type of stuff in order to release instead of doing literally anything with me? ive calmed down now it’s been a few days but ive been very snappy with him lately just can’t get the thought out of my head. i want to talk to him about this just to ask why but i know when. i ask him he will be embarrassed and then have a go at me for going through his phone rightfully so. i wish i never looked. Any advice on how to approach this?

Sorry if ive done this wrong i really only use reddit to view.

TL;DR i went through my partners phone and found something completely different to what i was looking for. now i can’t look at him the same.