About this guy comin back after 3 months?

iv been involved with a guy 22 months within them he went for 5months came back said he was depressed loads stuff goin on i was like ok then now hes gone missin 3 months and txt me saturday its only casual nothin serious only i really like him wich am shure he knows i txt bak who is this then i realised it was him just dont know why u acts like this better stil what 2 do any answers would be great thanks xx