When you say "Soy muy noviera (noviero)" it means you like to have a lot of boyfriends, or girlfriends in the case of a guy. It doesn't necessarily imply that you like to have them all at the same time.
But this post isn't exactly about that. Instead, we're going to talk about the different stages of relationships, and it all starts with meeting someone. Once you meet (conocer) someone, you start off as friends, amigos.
If you decide that you like each other's company in that special way, but not enough to be an actual couple, then you're amigos cariñosos or perhaps amigos con derechos. Spanish has a number of ways to describe relationships like this. We say friends with benefits. Just to be clear, friends with benefits is a way of saying you hook up with (ligar) someone just for the purpose of having sex.
Once you decide to become exclusive, an official couple, you're enamorados. We would call this dating, in a relationship, or if you don't mind a high school flashback, going steady. I suppose the correct term would be courting, or the courtship. Although to be honest I can't remember the last time I actually heard someone use those words outside of a movie that takes place in the 1700's.
Once the official peticion de mano (marriage proposal) has taken place, and you have a comprimiso de boda/matrimonio , meaning you've decided to get married, you officially enter the noviazgo phase, the engagement. The official title of a couple at this point is novios, although you'll hear the terms pareja or enamorados.
The interesting thing to note about the words novio and novia is that they mean boyfriend/girlfriend as well as fiancé/fiancée. A more accurate translation for boyfriend and girlfriend would be enamorado/enamorada, but novio and novia are what you'll hear the most. How do you know when novio means fiancé and not boyfriend? The context of the conversation. Or you could simply ask "¿estas comprometido?" - Are you engaged? There's also prometida/prometido which undeniable means fiancé/fiancée, but isn't always used.
Once you take the big plunge and go through with the boda (wedding), you're now in the stage called matrimonio, marriage - and you'll be known as casados, formally known as husband and wife, marido and esposa.
While marido and esposa are the official terms, you'll also hear mujer (woman) as a synomym for esposa, without the negative baggage that the word "woman" carries in English. And esposo is another word for marido. You can even say "mi vieja/viejo" (my old lady/man).
Sadly, sometimes marriage (matrimonio) just doesn't work out, and then you divociar (divorce) and become divorciados (divorced). That is, after you separar (seperate) and become separados (separated). But if you're lucky (suertudo), you reach the final stage of marriage, "till death do us part". Although some people might argue about the lucky part of that.
That's it, a crash course on the in's and out's of the relationship terminology in Spanish.
Espero que te sirva.
I hope this helps