You should know what you are in my life and how we have defined it, and unless we are moving in together or getting married, it is no ones business but ours, how we define ..... Two people make it official by talking about it and agreeing to a relationship together officially. For some, choosing to date someone exclusively happens once sex is involved.
Dating exclusively is just dating one person at a time for a short period... Both of you need to open up, talk and communicate about being together in a relationship. If you have sex with someone after 3-4 dates, does that make you a boyfriend/girlfriend?

It was established early on that neither of us date multiple people at the same time and that we will be/are exclusive.
As I said, a distinction is made occasionally when we talk. Talk to your boyfriend to get things squared away!!!
Part of me feels there's no difference since we act like BF/GF; however, there seems to be a distinction made during conversations with my....well, the guy I'm dating exclusively.
We've been exclusive since the beginning (2 months ).
I didn't date anyone who was looking for a relationship unless she was willing to date exclusively while deciding whether or not a relationship might come from it.
All it meant was that we weren't going to be going out on dates and/or sleeping with anyone else while we were waiting to see what happened with respect to a relationship.
Do you want the other person to have sex with other people while they have sex with you?
The two of you may also choose be exclusive out of respect for one another and safety. You may choose to see them exclusively to see how things progress without without the distraction of dating anyone else.
The more critical it is that you agree on meanings, the more imperative it is that you create your own agreed upon glossary of terms.
Lots of manipulative and/or irresponsible people will try to use word definition differences to get you to do things you ordinarily wouldn't or to side step their real responsibility for what ever they do.
If so, a thousand interpretations of a labels meaning is not going to help. I am curious if other guys make the same distinction since I've been out of the dating scene for an embarrassingly long time. You become bf/gf when you don't have to call up for dates and you just assume that you'll be spending time together except when one of you has something planned for which the other cannot be included for some reason.