@Dadaist - I'm not sure that you've read @MadCatLady71 post properly...
@MadCatLady71 - have you read bell hooks? It sounds a lot like the way she talks about love, as an action rather than a feeling. my partner is reading one of her books at the moment, and it's really interesting.
Regarding the substantive point that you're making, though, that it's not possible to do that with more than one person, I'm not sure I agree. I think what is often common for people who are monogamous, is that they think about their existing relationship and multiply that by two and can't see how there is enough time. But you have to remember that, generally, the person you are loving also has other partners - so the emotional labour of love that you outline is shared collectively, rather than in just one dyadic unit.
I have two partners, for full disclosure, and they each have (at least one other) partner. One of my partners lives with his partner of many years, they own a house together, my other partner lives alone (as do I). His other partner lives several 100 miles away, and they see each other just once a month. None of our relationships look 'the same', but there is a lot of love and care in them, expressed in different ways, and we definitely work as a wider collective unit sometimes.
I think it's a different 'way' of loving someone, but I don't think that it isn't love. I also don't think that it's for everyone, and that's also completely ok. I do, however, think honesty is really important - if you're going to love more than one person, they need to know about that. And, actually, when you are open about it, it can be really beautiful. I have a really good friendship with my partner's partner. We chat independently of him, and are emotional supports for each other...it's a very different kind of relationship to a normal friendship, but it's a really nice one.
Anyway, enough from me...