Well, I have had only 1 partner in any definition. I think if I had had more partners, it would really depend on the type of activities. I would consider oral and anal to certainly be sex and thus a partner count. I suppose my definition would be something like "If these people had an STD, could I catch it from this activity?" Not to be offensive, of course, but that seems like a good guideline to me.

Okay. I just got in this discussion again the other night with someone from Fetlife....... Anyone want to share?

I would define it as penis/vagina penetration also. Technically, oral counts as sex too and counts as adultery if you or your regular partner does this with someone else. But in my mind I wouldn't add to my 'number' anyone who I only had oral sex with. I require a chance of being fully satisfied for the number to increase and oral rarely does that for me.

I would never answer a question about how many partners I've been with, even if my husband asked. OK, I would tell girlfriends, but definitely not men.

I don't know. I mean, I kind of like to leave it up to people do define however they want. I'd probably go with "sex partner-broadly defined" as including oral and "sex partner-narrowly defined" as strictly intercourse (either vaginal or anal).
That ends my completely unhelpful answer!

I never ask. It's less of a Marco Polo complex than 'how much do I actually need to know?'. And all I really need to know is that a potential partner is experienced enough to have figured out who/what she is and what she likes/dislikes. Or at least has a fairly tangible idea. What's past is prologue. Or prequel. And me - I'm Star Wars classic.

However, as a man, I wholeheartedly encourage the padding of stats. Therefore, any definition to 'what constitutes sex' should remain rather amorphous, so it can be reshaped as needed.

I didn't have many before I met my husband, but for the past 25 years, only 1.

I define sex much as Adriana suggested: sexual contact with another person in which I could potentially contract or give a disease, including when safer sex practices are implemented. My definition is certainly not limited to penis/vagina penetration. It includes oral and manual stimulation, some forms of tribadism, among several other activities.

Generally I do not tell people the exact number of sexual partners I have had. I am regularly tested for diseases/infections & practice *very* safer sex so the NUMBER of partners I have had is not particularly relevant in most situations.

I take a don't ask/don't tell approach with my actual number of sexual partners. Quite frankly, I don't want to know the names of every person my partner has been with or the number of people. There's nothing I can do to change it, and it's not something I want to dwell on. If my partner's number is higher than mine I tend to view his/her as promiscuous, and if his/her number is lower than mine I feel like a slut. I know this reaction is not logical, but I also know from experience this is the reaction I will have - which has been to the detriment of some of my relationships.

The exception to all this is when I decide to be fluid bonded to a partner. Then there is a serious discussion outside of the bedroom about previous sexual encounters, disease testing, and what the limits of the fluid bond will be. At that time I will generally tell someone my number is less than - and more than - and ask they do the same.

**Please note that you can get a sexually transmitted disease or infection from performing and/or receiving oral sex. A woman can also be infected with some diseases if her partner uses his/her hand on her genitals or in her vagina and the partner's hand/fingers have open sores, cuts or any other lesions. (This includes finger penetration of the anus for both men and women.) This could actually include irritated hang nails.
I feel it is important this thread have this information as the general population does not seem to know this very serious information.**