I believe it's possible to love more than one at a time.
In reality though, keeping them both happy would be a full time job. I don't think you could have true love with 2 people at the same time without major conflicts of interest.
At one point, I tried to "date" as many women as I could at a time. During any given week, I would have been seeing up to 5 women. Sometimes two in one day. NOBODY stuck around for more than about 2 weeks. I got good at meeting them and shuttling them into the bedroom, but keeping them happy is a whole nother story.
Dating that many people was very stressful for me. I couldn't do it. I kept meeting women who I really liked, and wanted to spend more time with them, only to find out they weren't willing to wait in line behind all my other dates.
I have a friend who does just this, and has, for about 9 years straight now. I think he is deficient in the right neurotransmitters or something because he doesn't care about anybody. He lusts for women and once he's got them, he moves on. He's got a few women who put up with what he does and "love" him, but most are thrown away like garbage.
Monogamy, to me, is something you do for comfort and security. Some people require it to be happy, others prefer it, and others don't care for it. My taste for it comes and goes. I currently am seeing someone I love enough to provide her with the comfort and security she desires. I would never cheat on her, but I desire a lot more than one person can offer.
I think any women who would be willing to "share" me with another women would be too much of a hippy for my tastes.