Recently someone posed the question of whether or not it was cheating if someone was dating multiple people when there has been no discussion concerning being exclusive or committed.
The simplest definition for cheating is using deception and secrecy to "break the rules".
If you aren't in an "exclusive relationship" then you are free to do as you please with whomever you want. Unless there has been a discussion which expressively states that neither person will date or have sex with others there is no commitment.
However it is not uncommon for people to replace communication with (assumption).
Case in point if a couple spends a lot of time together in person and on the phone/email/twitter it's very easy for either of them to (lull) themselves into believing they are in a "monogamous relationship" simply based upon the time they spend together. Should this individual discover this person is also dating or having sex with others they're likely to react as if they were "cheated" on.
The "betrayed person" feels the other person should have (told) them they were seeing others and the so called "cheater" feels like since they (never discussed) being "exclusive" or "monogamous" they did nothing wrong. Its two sides of the (lack of communication) coin. Both people made assumptions!
Length of Time Dating
Time is the slippery slope. If you met two new people earlier in the week and set up a date with one for Friday night and a picnic/beach date set for Sunday afternoon with the other; most people would say you're not under any obligation to inform them that you’re going out with others.
If someone were to ask if you were in a relationship/seeing anyone "special" you'd most likely reply by saying; "I'm dating but there is no one (special)." Very few people would consider your activities to be "cheating" even if you're dating multiple people.
On the other hand if you continued to date these two people for (two to three months) your friends are likely to ask if the two people you're dating know that you are "seeing" others. Most likely overtime you would have had an instance where you were asked by one of the people you were dating to go out when you had plans to be with the other.
Lying by Omission
This is where it gets very dicey because most people will not admit they have a date with someone else. "I'm going to be hanging out with my (friend), co-worker, brother/sister."
This is an act of dishonesty. Whether you've had the "exclusive talk" or not people expect you to be (honest) with them. The use of the word "friend" is used to imply that there is no romance/sexual activity or interest between you and the friend. This dissuades the person you're dating from thinking you are romantically involved with others. It's lying by omission.
In the event the person you've been dating bumps into you kissing your "friend" odds are they will feel like you cheated (broke the rules) because you (deceived/lied) to them. This leads to you saying, "We never said we were (exclusive) and I never said whether or not my friend was a woman or a man....etc" In essence you are blaming them for being misled or "making assumptions". Therefore you’re still the "good guy".
Don't Ask/Don't Tell
Very few people tell the new person they're seeing at the (outset) that they plan to date others until they find Mr./Ms. Right or until they are ready to settle down. Neither party feels obligated to reveal their social/romantic activities. We don't want to know if we are competing with others and if we're dating others we don't want to risk the possibility of losing their interest by telling them we are dating other people. Therefore it's common for both people to have a "Don't ask, don't tell" policy during early dates. If a couple met online it is safe to assume that as long as their profile is available to be viewed by the public they're still "on the market" and open to receiving inquiries.
Perception is Reality
Nevertheless everyone wants to deal with honest people.Honesty is the cornerstone for all sincere friendships whether they be platonic or romantic.No one wants a "friend" that lies to them. Is dating multiple people and hiding/lying about it cheating? Lying and cheating go hand in hand. Perception is reality.
Is dating multiple people cheating if there's been no talk of exclusivity?