can't tell if I'm being used

I feel like my boyfriend is only using me for sex, but I don't think i should. Maybe I'm overthinking this. He's very sweet and always makes sure I'm comfortable and stuff but lately immediately after we finish he just says bye and leaves. I want to tell him but I don't wanna seem needy; should I just not say anything or word it in a specific way?

Edit: what happens is basically we make plans to hang out, and we do, and then things escalate usually because of me. Then when we're done he says he wants to hang out with friends or go to bed (it's usually late when he comes over)