A bit of a rant. One of the things that annoys me is the application of marriage-related terms to dating. The most common culprit is the word 'monogamy'. If two people are dating, and they are exclusive, they are not monogamous unless they are also married to each other and only to each other. Further, if two people are married, and the marriage is an open marriage so they are not exclusive, they are monogamous if they are not also married to each other. A bigamist who has a sexual relationship with only one of his wives is not monogamous. The next time you see a news article about a study that has shown seagulls (or whatever) not to be monogamous, think a moment about whether you thought they ever got married in the first place. The next time someone tells you about how gophers (or whatever) have or lack genes for 'monogamy' ask, "Do they have genes for white wedding dresses?"
The application of 'monogamy' to agamous situations (yes, 'agamous' is a word, although I'm adapting it in this case) is one of a number of instances in which we have a sort of 'creeping monogamy', in which just ordinary dating comes to be burdened more and more with the expectations that only make sense in the context of the peculiarities of that very peculiar institution, marriage. (This is one of the great irritations I have with this imperialism of the word 'monogamy', although by no means the only one.) There are so many better words for whatever you want to say than 'monogamy'. I am not monogamous because I am not even married. I cannot be monogamous until I marry. I can be faithful, loyal, exclusive, but not monogamous. If I become married, I will be monogamous unless I become polygamous. This all makes perfect sense. Using 'monogamy' in any other way makes no sense whatsoever.