Yes, but...

Assuming things go well, some time down the road you are going to (most likely) want to go to the next step and establish a monogamous relationship.

If you have already had the conversation that you are "dating other people," and now you want to stop dating other people and be monogamous, this is a happy, heady moment, full of excitement and potential. You are making a commitment. You are asking the other person to join you in creating something special and unique between the two of you, and move to the next step, hand in hand, together.

Alternately, if you haven't already made it clear that you are dating other people, this conversation is now a nerve-racking exposure of the potentially relationship-destroying admission that you have been shagging other people all while dating this person. It has the potential to be a bombshell admission of duplicity.

And I thought you liked this person?

So why not head it off at the pass, be up front and honest and true to your word at the beginning, and set yourself up for a smoother ride in the future? Seems like the healthiest course of action, to me.

(And yeah, mentioning your suicide attempt on the first date is kinda psycho. That falls under my "don't be a dick" comment in the previous post. :-)