I'm bipolar. I've had suicidal thoughts a lot. I talk to my psychiatrist a lot about them. Despite that, I've only been committed twice. Once, during my initial diagnosis when I was homicidal (the suicidal thoughts were a secondary consideration) and years later after injecting myself with 2 bottles of insulin when my medication wasn't working because I was throwing it up everyday. (Started taking a new medication that caused me to upchuck; everyone told me to "keep taking it, the effects will fade." Didn't.)

The bar is pretty high. The fact that you're seeing the therapist is indicative that you don't plan on following through on the thoughts and are seeking help, which are points in your favor. Also, at least in my case, my psychiatrist has offered to hospitalize me if I felt that it would help me through the rough patch I was in -- but I was free to turn him down, and did.

Psychologists and psychiatrists outside of the psyche ward are pretty decent people who don't assume the worst. You're right to avoid the hospital itself. Frankly, my time in isolation and observation (I can't wipe my ass without you watching? Really? Here, let me shit on the floor so you can busy yourself.) was fucking bullshit and pushed me closer to suicide, to feeling powerless and worthless, than any other experience in my life. I can guarantee you the next time I "try" will be my last -- I won't be going back to the hospital.

Funny side story: my insurance company disagreed that I needed to be hospitalized in the psyche ward during the last incident. The hospital had to eat $25k in charges because of the contract between the two - if the insurance company disagrees with the medical need for hospitalization, the hospital doesn't get to bill me.