Recently got a boyfriend and he told me he was seeing 2 other girls. What do I do?

Ok. Good luck

Last month, I had a guy ask me to write a story for him. I agreed and asked what he wanted to contribute etc. We had surprisingly good chemistry! He's an American, so he got flustered at my casual use of terms like "Dear, Love, etc." He was adorable, we would get lost in tangents and have so much fun writing the book. He ticked all the traits of my dream guy: quirky, shy, excitable. And he was a tease and easily aroused. It quickly became... lewd (my doing) and we were going through the motions. We got more and more intimate and we were freely saying "I love you" and such. Things were going great.

Then just last night, he tells me that he may have been cheating on me. I said "explain" and he said he has 2 other girlfriends. At first, I was shocked because he looked like he would struggle to talk to a woman, let alone have 2 at once. I felt stupid because he did ask me about how I felt about Polyamory. I had a really rough time in high school. It was battle after battle with my mental health but I swore I would be never dragged back. I thought this guy would be the beginning of a new me. He helped make me feel confident in my skin, feel mature, and just okay.

Understandably, I got mad. I told him "What the ****?!" I wondered if it was a trick to get nudes and to get someone to write for him. He said no, that I made him feel all the things he made me feel. He asked if he dumped the other 2 (who don't know I exist) would I take him back. He lives in Texas, so I can't make sure he'll be chatting behind my back. He swore on his father's grave that he'll be loyal.

I said we should sleep on it and he agreed.

What should I do? Should I take him back?