How to tell someone you are depressed

How do you tell someone that you are depressed? I’ve been depressed for a while now but it’s affecting me more now than it has before. I think about suicide everyday. I don’t want to feel this way anymore and I want to talk to someone or get help but I don’t even know how to open up to people. I mostly want to tell my SO bc I’ve almost started crying in front of him multiple times but not to where he notices. I’ve also been super sensitive lately and he’s caught on to that. Anyways I don’t want to make this super long, but if anyone could give me advice or tell me how they told someone else that would be nice. Thanks:)