He started acting different around two weeks ago, I thought it was because I hadn't pushed for more yet, I opened up and told him we could try seeing each other more, see how it goes because I enjoy his company. I didn't mention a relationship, I said that I do really like him. He suddenly backed off & said he doesn't know because he didn't realise he would like me this much from doing friends with benefits because he wanted to sort himself out before another relationship. He blanked me for 5 days. He came back apologising saying he's scared, he doesn't want to disappoint me, he assumed I would stress him and his last relationship made him that way. That he can't afford to take me on nice dates and he's self conscious. I said it's fine, that I'm pushing him for nothing, that I've never mentioned a relationship and I don't need expensive dates I only asked for his company and he seemed calmed. 2 days later we argue and he tells me he will never want me, he gives up & he's sick of the drama that it's not working. This was our first argument. He's ignored me again for 4 days so far.
How can somebody change so quickly? It was going amazingly well. He was the one who initiated us to be more than friends with benefits, not me. What did I do wrong?