What should I do about my boyfriend?

Me and my boyfriend have been together for 16 months, i a 16 and he's 19, recently he's been acting very strange, i had a majorette performance that he said he was coming to but *slept in* when i got in touch with him he said his friend had not enough petrol even though they went out and he said he was too busy with his friends. He invites this girl in his house who he knows i don't get along with and she threw our photo on the floor when he wasn't in the room. We had a great day last thursday but the next day he wanted some space, said he'd been thinking it fr ages and didn't know what to do, now he's barely speaking to me and when i saw him for half n hour yesterday he only kissed me once and when i went to kiss him he turned and made me kiss his cheek, I;m supposed to be staying at his on wednesday because i'm leaving school but now he has to *think about it* He is unemployed, blows all his money on beer within a day of getting it and always makes me go to his when i'm not allowed and never comes to my house anymore, now he says he wants to break up but hasn't *decided* he told me when we irst got together that he never splits up with anyone unless they cheat on him and leaves it to the girl, he's been badmouthing my family, going to clubs even though he *hates* them and never has time for me. He argues with me over nothing says "It's not you it's me" *cheesy* and says "you could do better x" What should i do? (I love him) xx thanks, Kathryn xx