Hands up, this reflects well on what happened in a previous relationship of mine (though to a much lesser degree, I think). The both of us were insecure to one degree or another and had our demons to confront, albeit we never did so things just fell apart. I'd like to think that, given time, things would have been okay...but that ship has long sailed. For me, I never felt I was making my partner happy. I tried doing everything to make her happy, to feel safe and secure about herself. Never worked. There would always be something else stopping her from being content. Like you said, it made me feel like a terrible person (I spent some nights crying myself to sleep because I felt like the worst partner ever), and it got to the point where the same would happen to me...because I just felt so bad, any attempt on her part to make me feel better was "never enough". Sex and communication were big issues for us and my partner at the time rarely initiated intimacy, I never once felt attractive throughout the entirety of our relationship, but that was an insecurity I had always had reinforced by certain behaviors. Definitely something I've worked on over the year, like you I've been to therapy, so I feel confident that next time will be much better in that regard.
@reinventmyself
It's unfortunate you had to go through that experience, I can't imagine what it would have felt like being in your shoes. Just know you did enough to make the situation better and, like polaris said, you did nothing to provoke that reaction from him. Unless he were to have sought professional help, nothing would have changed.