You were upfront about it, he took it badly which is entirely his problem. Whenever I've been in a similar position, I've always tried to be fair and honest with people. It's never easy, but in general most musicians take it on the chin and move on.
I've only been sacked from a band once. The drummer (a college educated jazz guy with ideas frankly way above his level of success/ability IMHO) who had started the band told myself and the singer/keys player that he had another project he wanted to work on and was folding the band. I found out a couple of days later that him and the guitarist were advertising for replacements on joinmyband. The singer (who was much younger than me, and was writing a lot of the material) was pretty upset about it and she challenged him in an online chat group we had set up. It was a joy to watch him squirm and try and weasel his way out of it. If he'd just been honest and told us why he wanted us out I'd have respected him and gracefully accepted it, even if I didn't agree with him.