Office Romance - 'M40' and 'F32'

I don't even know where to begin. I '32F' started seeing this guy from work '40M' he was so fun and a breath of fresh air when it came to the office and things going on in my personal life. What started as harmless office flirting grew to texting, calling, FaceTiming nonstop over the course of a year. He was always up and down emotionally and it was hard for me to get a good read on him but I kept chatting because I was really into him. Well a month ago, he and I slept together for the first time. We have this chemistry like none other and are literally so similar. Our interest, values, hobbies, etc just aligned perfectly. He and I are like the same person so I feel like that also bonded us a lot. The other night while texting he hit me with an "I....U" so I said to him "Awh you like me? That's sweet" (knowing all too well what he meant), he responded "yeah ish...lol" admitting later that the .... was love so even though our agreement was just to have fun, he fell and so did I. After this, we slept together again. He then started to pull away a little and now he said he wants to take a little break. He wants to do it for his kids because his ex is "crazy" and he is worried if he has a relationship she will become evil and vindictive. I just feel like it's an easy out to use his kids but I'm just crushed. I really thought he was my person. I just keep replaying things in my head. Like where did I mess things up? I normally don't let things like this get to me and can typically move on but like I said, I fell hard for this one. I realize office romances typically don't end well but that ship has already sailed. Do I tell him how I feel or just let it go and move on?