Do you really want to bring up the fact you were on a date with someone else while on a date with someone? Am single, you're not (Emphatically not!), I should just shut up and take notes.
Well, either you are "dating people" or you are "lying to people serially". If you do not address, up front, that you are actively going out on dates with other people, you are lying by omission. And that's not a great place to start any relationship. So be honest and true with everyone you meet. Look them in the eye, tell them the truth, and ask them if that is OK with them. This is Consent 101. If the two of you are entering into the date with different understandings and intentions, that ain't gonna go well for anybody. So. You look her in the eye, tell her that you are dating other people too, and ask if that is acceptable to her. If not, then she can move on to someone who will lie to her face, and you can move on to someone with reasonable expectations and some sense of pride and self-confidence. If she looks you in the eye and says, "Yes. I accept that. I'm also dating other guys, too," now you get to see what kind of man you really are. Can you take that? Are you confident enough in yourself and your value as a relationship partner to invest your time in someone who is honest with you and appreciates your honesty? (Protip: There is only one correct answer to this question, because if you answer "No" then you are not ready to be out there dating, and you are doing a disservice to your dates.) Caveats: Yes, of course there are ways to bring up conversations with other women in polite and conversationally-relevant ways. There are also ways to be a dick about it. So don't be a dick about it. Whether or not you are female or polyamorous or whatever, there is a LOT of gold in the unfortunately titled book "The Ethical Slut". This is a great primer for how to treat other people as actual people and human beings, rather than tools for your pleasure. Consent, open conversations about "hard" subjects like contraception, etc, etc, etc. Check it out.
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. :-)
The trick to successful dating to to no over-communicate. Try not to verbalize anything that can be communicated by other means. Especially relationship expectation. When my wife and I started dating she verbalized a lot of expectations that I misunderstood. I mostly ignored them and told her she should date other people because I could not provide what she had verbally asked for. Well it turned out that she didnt actually want what she had verbalized and was trying to communicate something else entirely to what I understood at the time. I only found that out about 5 years later after we got married and were talking about it casually.