For me it has been totally dependent on where my head is at. I have been through phases where I definitely was not in a headspace for a relationship, and when I was trying to be "normal" and date people, I would run out after about three dates, usually without sleeping with them because it was seen as some sort of "seal the deal" thing. So I went through what I jokingly refer to as various "arbitrarily slutty" phases--which I should really rename because I think words like "whore" and "slut" are just generally harmful loaded things to perpetuate. I think they were incredibly helpful to my development as a person, because they put me in situations where I had to learn to communicate my needs and boundaries very clearly. Generally I tend to vascillate between two ends though--either I'm uncommitted and having a fair amount of casual sex, or I'm with a long-term partner or dating several people with the intent to find a long-term partner. But I don't use casual sex as a "rebound" as Ms. Reed is suggesting, or as "prep work" for a monogamous relationship. After a bad breakup, I generally have to take an extended break just for myself.
I think I'm just not in a place to want or deal with polyamory. When I am in the head space for monogamy, I don't really crave anything (or anyone) outside that--and I'm bisexual, so I guess that's a little unusual. When I am not, I also tend to not be in a head space for any kind of commitment either, but then I have struggled with commitment in the past.
Also, re the virginity/what-is-sex debate, since the primary significance of these acts is experiential and personal, these are totally subjective definitions that should be seen as a personal mechanism for organizing and relating to experiences, not a social metric for judgment. If we let go of our assumptions about what "normal" sex is, we find we all have boundaries of things we are uncomfortable with, things we are only willing to do or attempt with certain people (real or potential), things that are totally within our comfort zone, and acts and situations that hold particular meaning for us (good or bad). For example, many people with open relationships agree to reserve certain activities, often as simple as holding hands or kissing, for their primary relationship, even though when using a traditional progression model of sex that puts vaginal penetration as the final and ultimate objective of sex, it would seem illogical to attach more meaning to "lower" activities than "higher" ones. Intimacy comes in all kinds of flavors and is fundamentally shaped by the experiences and identities of the intimate partners. Attaching tons of social importance to ideas like virginity, especially using a rigid heteronormative reproduction-centric definition as is commonly applied, doesn't do a whole lot but harm people through arbitrary social shaming. If individuals choose to attribute special importance and status to vaginal penetrative sex in their own lives, that is totally fine--but that is THEIR decision, and not anyone else's to enforce upon them or shame them for their adherence to or deviation from that standard.
TL;DR slut-shaming is Rude and the meaning of sexual acts is individually determined so don't worry about it too much