Have to get this out..

So I recently got caught up on my boyfriends Snapchat score & noticed it was climbing really fast. I know you can only get points for sending video/ picture chats & it started to overwhelm me. I went about it the worst way & logged into his snap from another device. I wanted to be wrong about my feeling so bad but I wasn’t. Turns out he was chatting with 3 random women. The conversations were not innocent. Not any nudes but very flirtatious. I ended up confronting him about it & he flipped the whole thing on me. Kept calling me shady & wouldn’t let me get a word in. He ended up telling me he was done with this relationship but today everything seems normal, as if nothing ever happened. I’m so confused. He was dead set on his decision last night. We have 3 kids together. Been together for 5 years. We live together. I know he messed up & it killed my trust but I can’t see myself just letting our relationship die. I love him so much but this hurt me. People make mistakes, I’m not perfect either but he just couldn’t own up to it & im stuck in what decision I need to make. I can’t talk to family or friends about this, I’m too ashamed. I feel so pathetic & weak today. I just don’t know where to go from here. Am I pathetic for wanting to make things work?