Concurrent Dater - though this dater is not out for just fun, they manage to have Fun and seek something serious simultaneously. Most normal adults fall into this category. They are not opposed to a relationship, but not making being in one their priority.
Concurrent daters go by how they feel and who makes them feel that way the most and the best. That is how they choose who to date monogamously, or be in a relationship with. This type of dater, if doing it right, is dating multiple people at once and providing each equal consideration, until one self-emerges. Most of us have been this type of dater without giving it a title. We meet two different people on two different occasions and date them both for months. Then, for whatever reason, you stop dating one and continue with the other -- sometimes into a relationship. You were dating them concurrently; and considering each of them for something serious at the same time. One just somehow emerged ahead of the other(s). This is healthy if you can balance time, attention, and honesty. The concurrent dater is also in the fortunate position of being able to date either dating type, serial or monogamous. They don't mind the serial dater because they are dating other people. They don't mind the monogamous dater because they are also seeking something serious. Dating multiple people only succeeds with honesty and transparency. The successful concurrent dater, the most likely to emerge with a relationship, is honest and forthcoming about everything. They know that trust is the most attractive quality when seeking a relationship.
Monogamous Dater - A monogamous dater lives up to its prefix, likes to focus all their attention on one person at a time. They see it as being fair to the person they are dating as well as themselves.