What is going on with him, when he know hes being immature about this?

I have been sorta dating this guy for 3 months now. We spend every evening with each other when we get off work. We have had intimate discusions. He knows things I have never told my best friends. All of a sudden, he says he cant talk to me anymore. Says he just makes a horrible boyfriend, and cant talk to me or spend anymore time with me. But the next day he texted me all day long and hasnt stopped this for days, Keep in mind that the week leading to this event I was out of town for 7 days. We did nothing but text back and forth, he told me constantly how much he missed me and could wait to see me.The 3 days after I got home were perfect. I called up one of my girlfriends that has known him his whole life. She tells me that this is what he always has done. Sometimes he just gets in these slumps and talks to no one unless he has too for weeks. I had bad relationships in the past and this one seemed so right. What does all this mean?