Everyone rambles on this site. I think it goes with the territory. I'm a big offender myself.

Your fear of being honest is understandable. I believe that in most states, there has to be an iminent threat of harm to yourself or others before you can be involuntarily commited. You can probably check the laws in your state.
When I was in my early twenties, my parents and family Dr. tried to have me commited because I had said I was thinking of trying to kill myself again. They kept me the mandatory 72 hours, then let me go. The funny thing was, they did it on a Friday night and there was no psychiatrist there until Monday, so I spent two days wandering aimlessly around the ward. On the third day, a psychiatrist had me sit down on a bench in the hall, asked me if i was a danger to myself (which I was but wasn't going to admit), I said no and he sent me home. The point is, even if you do wind up with someone trying to commit you, its pretty easy to get out again.

The relationship between the therapist and patient can take a long, long time before there is really trust between the patient and therapist. Unfortunately, I had a string of bad ones, so four decades of depression, suicidal attempts and ideations plus SI, I'm still too distrustful to go to one. If you have a good one, honesty may pay off. IF you think about it, all the psychiatrist has to go on is what you say, your body language and tone of voice. Thats it. Unless you let him know what is going on, you may be missing out on something important therapy wise. If you have concerns, you are fully within your rights to ask him bluntly what his policy is on talking about suicide, suicide attempts or urges. If you don't like what he says, he can't commit you for asking a question. You could just say you were curious. Psych wards are full already. They don't want more patients unless they really have to be there.

One night I cut a vein in my arm, suicide attempt, and my parents took me to the hospital ER with my blood soaked jacket and begged them to commit me. They wouldn't. Its not that easy.

So now I have rambled on. Put out a feeler on how your therapist handles suicidal thoughts and if you are ok with the answer, honesty is the best thing. If you don't like the answer, or feel that you can't trust him, then you have the wrong therapist. Without the trust, the therapy won't work.

Sam2