My ex and I have been broken up for 8 months now. He has moved on and had a relationship but it ended quickly. As it started he said he didn't want me in his life anymore then it ended so he came running back to me. He has said he doesn't want me in his life three or four times now but always comes back or makes contact eventually. How do I know if this time he's serious and doesn't want me in his life or is he just playing his usual game? Also, why did he keep coming back previously if he supposidly doesn't love me/care for me? Recently, every now and then he would reminisce on old times and say that I should be beside him.

He keeps playing these games because you keep taking him back.
You need to put your foot down and say "no more" He uses you like the Motel 6. He comes and goes and checks in for a while with you when he gets tired.
Why would you even want them back?

Thing is I don't take him back every time, I guess you could say I play his games back to a degree, I don't let it all just suit him. I'm only wanting friendship not him as a partner because he is a great person but it didn't work for us being together. We have been through a lot together so I value the friendship but don't understand why he's acting like this when it's a friendship not relationship. Basically cut all contact even if he tries to contact me again?

Yes, because he is not even being a good friend

Very true, thank you :)