Me and ex split up two weeks ago. He broke up with me because he found the way I communicated "guilt inducing" and that, as someone who works with people who have mental health problems, I should not express criticism to him in ways that upsets him because I should know how he thinks 
Ex is extremely introverted, shy and has little relationship experience. I was his first partner in 5 years. He has one previous six month relationship from his teens. He doesn't enjoy casual relationships. I think that is relevant.
Anyway, the relationship itself was very nice. We built a really good friendship before we became romantically involved, and dated for a long time before we entered into a relationship. He was very considerate and just generally a nice guy. I thought I had met The One. He told me the same thing, he spoke to marriage, kids etc.
There were a few red flags during the early days. He cried seemingly out of nowhere about things from his childhood and always told me he was "broken". A lot of our conversations were sad. I too had a bad childhood, and was happy to have conversations about it with him if it helped.
He also described himself as a creature of habit. He had a daily routine that made him feel comfortable, and in his words, less lonely. This involved excessive amounts of exercise in the evenings. At first, he was happy to adjust this to accommodate coming to visit me, especially at the weekends. But, as time went on, he seemed to insinuate that I was angry that he did his exercise in the evenings... this was never the case. I have a heavy workload and various interests that keep me busy! But, when I was staying at his over the weekend, I was obviously excited to make dinner/see him when he came back from his club. But he seemed to pick apart things I would say like "What time will you be home?" to mean "I am angry that you're not back now" No matter how calm or nice those types of messages were, the outcome was always "you are criticising me".
So, I stopped bothering with normal texts of when he would be back - because, deep down, I probably thought to some extent I was being unreasonable and perhaps a little needy.
Anyyyway, there came a sticking point about three weeks ago in which I disagreed with a boundary in a relationship. A very small, almost insignificant boundary. We had previously discussed it, and he had made his feelings clear on it - he didn't like it, and doesn't think it's the right thing to do. He made a point of saying this with no hinting etc from me. Then I found out that he had done the exact opposite of what he said he would do. After a shite day at work I rang him and said:
Me: Why did you do that, when you said you wouldn't?
Him: I don't know.
Me: It makes me feel insecure.
Him: I won't do it again. I'm going to have to go now.
Immediately after said phonecall I text: "sorry for my insecurities there, just confused as you mentioned you wouldn't do it. phonecall wans't the best way to bring it up. Let's talk tonight. Enjoy club"
He didn't reply for three days - and I didn't contact him either.
When we eventually spoke, he said that I didn't even check up on him over those three days. He said I was a nasty person. Said I was being very manipulative and underhanded in criticising him. When I tried to reply to what he was saying he would tut, shake his head and avoid eye contact with me. He said breaking up was probably for the best because he couldn't be with someone who made him feel guilty.
... the only things that he mentioned which made him feel guilty were the texts about where he was/when he would be back, and this small (insignificant) boundary thing
I didn't see the breakup coming, so I didn't really react that emotionally apart from sending a text apologising (but I don't know what for).
Anyway. I gave him space for a week and a half and then asked for a chat. We chatted over the phone for 6 hours. He then had his dinner, did his exercises and then rang me back for a further 3 hours.
In that phonecall, the breakup was not discussed at all. He acted as if nothing had happened. He was light and breezy, flirty and just laughing with me. This was on Sunday.
Monday comes and I send him a very light-hearted message about a news story we had spoke about - he responded within seconds. When I later replied - he didn't reply until Wednesday. And he was cold and distant in that text.
What the hell is going on?
I am usually quite collected and cool in relationships, especially breakups. I've done the whole begging for them back routine before, and vowed never to do it again. If someone finishes with me, I am able to focus on other things. But this has got me up all night, feeling/being sick, unable to eat, headaches, irritable etc. - mostly through the confusion.
We seem to have broken up because he can't take (fair?) criticism. He can treat me with contempt and then have a 9 hour phone conversation, then act like nothing has happened ... what's his game here.