Why did my ex disappear again?

I'm sorry. It sounds like he is not going to change this pattern anytime soon but likes the fact he can go back to you because you, even though reluctantly, let him in. He really does like you but at the same time needs his space. My boyfriend is similar but it has never reached months for us. I think he does care but is still young or young at heart and doesn't know how else to get this space besides what he had learned from his parent. If you want him to grow out of it I guess you could get a combining factor, test if he is like his father or it is just a phase of life, get a dog as a couple when you are back as a couple. If you let him back in, if he is the love of your life you should give him a second chance.