Ghosted after 4 months of dating, was it my fault ? Help

I live on a very small island with roughly 100k people.I started dating this guy I was familiar with, well we started out as friends and I even helped him through his last break up.Encouraged him to get therapy etc.We both have small kids, he has a daughter and so do I. After he claimed he was ok, we started dating, it was going well. I explained to him what happened in my last relationship and how I spent an entire year getting over what transpired and that I don’t want to go down that road again. I spent 8y on and off with my ex and it not only hurt me but my daughter. He assured me that all will be well and this was the finish line for both of us because he’s always wanted to be with me and he can see a future with me. We decided to be exclusive after a month of dating. We were watch videos one night when a random message popped up, it was a kiss emoji 11:25pm at night. I was a bit uncomfortable and asked what that was about, he assured me it was just a friend and they never had anything, never slept together, nothing! I took his word for it at the time, but something didn’t sit well with me, something wasn’t right! It came up again weeks later, the story then changed, that they had something but that was way before me. At this point I was so upset because he lied to me. By this time he had already made his way into my heart and my daughters, invited himself to her bday event and filled her head with “oh you’re a big sister now, I am going to marry your mom”. I had already met his daughter, so i felt like this guy was serious because men don’t just bring their kid(s) around like that unless he is serious about a woman. The girls loved each other and my daughter was so happy to be a big sister. He spoke about marriage and even started sketching our house and had me driving around looking at properties because he wanted me to choose something I would be happy with. fastforward….I later found out that the same girl was just before him and i started dating and he hadn’t shut down everything with other women as he claimed. He was still talking to theses women. He accused me of being distrusting and insecure. I was upset and hurt, we had an argument about it. He said he needed space, that scared me, because I already let him in so deep and he already brought the kids in. Looking back I did’t give him space, i kept calling and texting asking him to lets talk and fix what ever it is, even though I was not at fault and the break down of trust was not my fault. I wanted us to fix it and move forward. First, he said it was my fault, then he said he wasn’t ready for a serious relationship after pursuing me and convincing me that he was. Then he said oh its not you it’s me, you’re too good for me. I was so upset, I told him he would have to explain to my daughter because he brought her into this and I am not gonna break her heart. He hung up, blocked me and I never heard from him again. I later found out he was still flirting and asking other women out on dates. Also, he jumps from relationship to relationship. I feel so led on, and what bothers me the most is that he brought the kids into his game. I am so confused and so hurt. We went from planning a future on a Sunday morning to him not ever speaking to me again by Tuesday morning.