We're on a break...

So this past weekend, I uncovered a couple pictures from two years ago, when we first started dating, of my boyfriend with another girl sitting in his lap. I immediately felt sick to my stomach because I had no idea who she was and why she was sitting on his lap in multiple pictures saved on my boyfriends phone. Now this isn't the only sign of unfaithfulness that I have found in our relationship, so here's a little backstory.

The first time, I had found him having an online relationship with some girl on Facebook. He was hiding it from my until I opened his phone to look something up and it was on the screen. He told me it was purely emotional and that's it. Another instance of unfaithfulness was another time we were looking through pictures on his phone, and he had a screen shot of a text from his "friend" Alexa that said "I love you."

So me finding the picture of the girl on his lap was the last straw. I asked for some space and a break from him to sort out what I was feeling and whether I wanted to continue in the relationship. That is what brings me here. I have no idea if I should stay with him or move on. He has apologized for everything, and I believe that he is sorry. I'm just scared that he is going to be unfaithful again since he's been unfaithful from the start of our relationship. I'm just so bitter and negative thoughts pop up in my head whenever I see or talk to him. Any advice is appreciated on whether or not I should continue seeing him and some advice to combat the negative feelings!