My ex sends me mixed signals, what do i do?

my ex and i have benn broken up for a while but he tells me we should just get to know eachother again. he like to call and tell me he loves me late at night and i always say it back but he ignores me in school and recently he is turning around everything i say to seem liike i am attacking him. he seees other girls and admittadly i have been having casual relations with someonje else because i wont commit to him if he acts crazy. what do i do?