Everyone has feelings about whether it's ok to be dating multiple people while you are getting to know someone. If you have strong feelings one way or another, you should let the other person know what is important to you. Most people don't have an expectation of exclusivity after the first date, but even if they don't expect it, they may still want it.
That's a contradictory idea, but often we humans are contradictory and complicated.
The two most important things are;
communicate your thoughts about exclusivity before you need to,
respect what the other person feels - even if it is the opposite of what you feel.
When I was actively dating I was often dating multiple people. I was very upfront (even before the first date) about the fact that I wanted the option to date more than one person while I was getting to know someone. I was clear and honest. I don't know enough about anyone after the first date to make any decisions about the relationship. The only decision I made after the first date was whether or not I wanted to go on a second date.
To me, the first few dates with someone are fun. You are sharing stories about who you are, talking about things you like and dislike, and you are doing fun things together like going to plays or sharing meals or hiking... or whatever you enjoy.
There were many reasons why I wanted to just date someone without either of us feeling the pressure of being in an exclusive or committed relationship. I also made it a practice to check-in after a few dates about how they were feeling.
Sometimes we would be on the same page, sometimes not. More than one time I had a date say that they would not date me if I was not willing to be exclusive before I felt ready. I was glad they let me know about that boundary and I chose not to see them again.
I also dated more than one person who let me know that they only wanted to date one person at a time (me) but they respected that I felt differently. Those were the people I continued to get to know better.
I think it's ok to date only one person at a time and I always respect the decisions made by others. It is not okay to assume that you are exclusive with someone before you have both talked about it and agreed. If you want it, talk about it and if the other person isn't ready, then don't shame or blame them into exclusivity.
It is not okay to date other people if you know the other person has an expectation of exclusivity. So ask what the other person is thinking and feeling and check in with them every few dates or every few weeks depending on how often you see each other. You may not like that the more you see someone, the greater the expectation of exclusivity, but it is a dating norm. So if you want to date differently than the norm, then clearly communicate it.
It is very common to have misunderstandings around exclusively and commitment because exclusivity early is common but not expected. Just because you are dating only one person (exclusivity) does not mean that you are in a committed relationship. Agreeing to be in a committed relationship means that you have had a conversation with the other person and agreed on what commitment means to both of you and you have both clearly stated your commitment level to the other person.
Don't assume you know what the other person thinks about exclusivity until you talk about it. There are many reasons why someone would want exclusivity after just one date, and there are many reasons why not. Understand what your feelings are and communicate them. There is no right or wrong way to feel about exclusivity. It's just how you feel.
In Canada, especially in Toronto, there is a growing acceptance of non-traditional relationships. Ethical non-monogamy, triads, situationships, open relationships, and the list goes on. People are happy forming relationships that are not just monogamous heterosexual relationships. The key to successfully navigating all of these types of relationships is open and honest communication.
Early-stage dating is no exception. Be honest about what your dating life is like and communicate often about your level of commitment. You'll find what you desire!