Love triangle situation- help

I know I’m going to get hate for this, and I’m sorry.

My boyfriend and i are in a tough situation in which we can’t tell anyone we’re dating. Other than my boyfriend I literally have 1 guy friend that I’m close to, and we’re close because he trusted me when he was very depressed and i convinced him not to kill himself. I should’ve noticed at the time but he sort of became dependent on me. He always talks about how worried he is that im going to leave him, and the issue is that I can’t tell whether that’s his genuine anxiety or whether it’s plain manipulation. So I’ve always reassured him that I won’t leave, that he’s a good friend, all that.

It was purely platonic. Until one day he told me he had feelings for me but he did it in a way that I deeply misunderstood. He said “I can picture us getting married one day” and I kinda laughed it off and when he asked if I could see it in my head I just pictured myself in a wedding dress and all that, because of course I can imagine anything. But then he thought I was saying i liked him back.

It probably sounds stupid. But he went from being so terribly depressed to so happy and I got scared that he’d actually kill himself if I told him that’s not actually what I meant.

And so i didn’t tell him.....

I know it’s wrong. I love my boyfriend more than anything and this eats at me every night and every day. I need to find a way to tell my friend that it was either a misunderstanding or that “I don’t have feelings anymore” and then get out of that relationship completely. I don’t know how out of my fear of knowing I’m responsible for someone’s death.

I don’t know.

Please give me any advice. And if you have something hateful to say, I’ve already said it to myself so just please try and keep scrolling.