An affair refers to a relationship that exists between two people which is sexual in nature.
But, it is not definite that there would be a relationship between them. date, that whether they will have relationship between them or not.
When two people start dating, they try to know each other in their date.
Jake and I saw differences between committed and exclusive.
We figured that exclusive simply meant that there was no hooking up with anyone else allowed: no making out, no dating.
An affair refers to a relationship that is mainly sexual.
A relationship, on the other hand, refers to a connection that exists between two people.
The key difference between an affair and a relationship is that while an affair is mainly sexual, a relationship is not.
It can be used in a much broader context to include romantic involvements, friendships, etc.
If I'm in an exclusive relationship, I can lie on the couch while she does stuff with her family.
If I'm committed, I'm doing that stuff with her family.
But, always remember that the serious relationships take time to develop, whereas dating can be planned and done within few days.