me & my boyfriend broke up, on christmas

we have been together for 3 years & this was the first real relationship i’ve had, we have been on again off again, but he always breaks up with me & tells me he needs “time” & “space” from me & being in a relationship but i always find out he’s on tinder & talking to other girls, he is very immature & i am trying to keep my distance from him & try to move on but it’s very hard for me. does anyone have any advice or anything that can help me.? this is very hard for me.