OftenBen I do not believe that if you do not disclose you are dating other people in the first several casual dates that you are lying serially or by omission. There are lots of things you may choose not to disclose in the first few dates and, as a date-e and dater, this should be understandable. There is a lot of past trauma, as well as past happiness, that may end up being relevant to someone you date that you probably should disclose at some point - that doesn't mean you have to, or even should, right away. If you unpack all your baggage, "full disclosure" style, on a first date, you're not going to get a second one. For instance, (fictional example), if I had attempted suicide in my past, that is something I feel a romantic partner should know. That is not something I think anyone should feel they have to disclose in the first, say, 3-5 dates however. You should try to figure out if you like a person and trust them, before diving into disclosures. I think honestly that includes "I'm dating other people." On the other hand, you should also always assume if you haven't had a conversation about monogamy, that your date could be and probably is dating other people. Especially, again, in the first 3-5 dates where you're honestly just trying each other on for size. However, I'm not saying this is a bad approach - I'm just saying i don't believe not disclosing it woud constitute a lie unless/until the dating began to take a more serious flavor to it.
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. :-)