Need some advice

So me and my boyfriend of 14 years have taken a "break". It was my decision due to the news I received on my bday. We have 3 kids together (4yr old. 2yr old and 8 month old). He's not the best when it comes to parenting ( works all the time and likes to be out and about) so i am more hands on then he is. He takes care of his responsibilities but just sucks at being there when i need him the most. So the day before my birthday, we were having a conversation and i told him my concerns etc. I shouldn't have said it but i told him he sucks at being a parent and gave him my reasonings and said if i knew this was the type of parent you were going to be then i wouldn't of had kids with you. I ended up going to bed and woke up the next morning (my bday). My daughter goes to wake him up and he wishes me a happy bday. I thanked him and apologized for the previous night and he just starts crying. He just kept saying we need to talk but not around the kids and walks away. I said whatever you have to say you can say it now. So he texts and say promise i will always be by his side etc. I didn't respond and preceded to get me and the kids ready for the day. So he comes upstairs and basically tells me that he's been talking to my cousin. They met two yrs ago and and met up one other time this yr and that's when he figured out it was my cousin. He said he got drunk because of the conversation we had the previous night and was hurt and decided to text her but thought he was texting another girl with the same name. And the only reason he said something was because my cousin told her mom and he was scared that her mom was going to tell me. He said he was going to cheat but didnt. After reading the texts, she clearly stated she told him to stop contacting her etc and that it wasn't right. I understand they both are wrong, but what would you do in this situation? I love him but I'm not the type to stay just because we have kids together. I wanted us to take a "break" so he can realize what he could potentially lose and know that he hurt me. Just want to see what you all would do in this situation.