Do you regret saying certain things? Or did you feel better releasing it?

Last time I posted it was after my EXN recontacted me for the 5th time after breaking it off with me (Luckily I blocked him so that was the last of it and I never responded). In the past I was either the one to break NC or he would and I would foolishly respond, and it would turn into something it never should turned in to. The last time a few weeks ago he tried to get me to give us a serious chance again, he said he wanted to go to couples therapy and reiterated how "amazing" I was- you know all those words that mean absolutely nothing coming out of the Ns mouth. For whatever reason I knew he wasn't sincere but I entertained the idea, kept him going, telling him I just need me time and that I wanted to take things slow basically telling him no, but not coming out and saying no, maybe in the back of my mind I was trying to take control so that I would be the one to finally say my piece and tell him I didn't want him this time around. Well low and behold I received the text "I just need to let go of us. I am sorry for taking you on this roller coaster ride...I haven't been alone long enough to know what I want", the day before he was professing his need for me in his life and wanting to take counseling. Anyway, I flipped out and responded basically telling him to 'F' off and saying stop screwing with me to leave me alone that I never deserved anyone like him, that he was a jerk and will always be one. I ended it with "I was in thise way more than you ever were, and that is sad... why do you keep coming back to me just to tell me were over, to make sure I'm still here?! I'm not anymore so, Take Care." It was a pretty long message, and I wish I had just replied to him "Okay, take care of yourself, I knew these words would come eventually", or just not have responded. His last message before I blocked him a couple weeks ago was basically, "see you are so immature and sensitive you can't even handle a break up".

I'm not sure why I'm still pining over this and regretting all those nasty things I said to him (not even really that nasty but I feel it came across as she's just upset and trying to hurt me how I hurt her), I kind of wish I had been the "bigger person" and not responded. Why do I feel in my head that now he has a reason to "justify" why I actually wasn't a good woman for him because I am immature and sensitive? Have you guys ever sent something you have regretted, do you think that sending something like that was out of line? I was seriously just so tired of this man coming in to tell me how amazing I am try to get me back, then when I show disinterest HE tells me nope nevermind i need to forget about us. I know I let him do that to me, but I just wish I had come out the bigger person.