My SO's phone 😪

This was quite awhile ago but I cant stop thinking about it.. my SO came home from work, he was out of town so the drive back was like an hour long, he was with other coworkers in the vehicle. He hopped in the bath and his phone went off. He asked me to look, I did was just a email notification but I clicked the recent tabs that were open and saw that my SO was just googling naked womens photos and looking at a ton of them. I was super upset especially since he didnt even bother trying to keep a conversation going over text with me even though he was doing nothing. I asked him about it and he said he was "bored" that's why he was looking at naked women. I asked him why he didnt text me than as he kept ignoring my messages or taking 10 mins to respond. He didnt have much to say. 😪 Would you be upset? What's the point in sitting there looking at naked womens photos? I've never done something like that to him. Am I overreacting? 😪

Edit: Yes he admitted he was looking during the ride home. I dont think he was jerking off as other people were in the truck.