how do you break up with someone whose suicidal?

i would to some guidance on this sticky situation. my boyfriend and i have been together for 6 months now and i think i’m frowning apart from him, i do love him but i don’t think it’s gonna work out anymore because he’s very damaging on my mental health and that’s dragging me down. i wanna make sure he’s safe but he doesn’t have a lot of good people in his life and he really only has me which is why this is so hard. should i stay for a little or leave because i have stayed with him while i feel this way and his depression gets worse. i feel as if he’s using me for my happiness and i’m basically his caregiver and not his girlfriend. what do i do?