Is it normal to be attracted to more than one person?
So, what the world doesn't yet want to recognize even though the evidence is continuously in front of us, humans as a whole are not monogamous. People are continuously attracted to people other than their partners, and we choose to ignore this and believe that it isn't relevant information about ourselves. It tells us things about humans that scare us. Women want to sleep with multiple men because it is their biological urge to procreate with multiple men, especially ones they've never met that are more alpha/dominant types, because from a biological perspective they are most likely to give you strong offspring. Men want to sleep with multiple women for the best chance of offspring.
It is completely normal and healthy. Did you know that in a man's sperm there are sperms whose only purpose is to find and kill other men's sperm? This means that our biology is designed around a woman having the sperm of more than one man in her at a time so that the healthiest of all the males will produce the sperm that wins out, thereby strengthening humans biologically. And everybody flips out if their partner "likes somebody else." Check out the book Sperm Wars.
We just have forgotten that humans have been having loads of sex with many partners all over the world...until the agricultural revolution that gave us cities and structure and religion that told us it was wrong if we had sex with more than one person. Check out the book Sex At Dawn which goes into the history of human sexuality. Modern times are like a brief flicker compared to how long humans have been running around the planet. Just because we are doing things a certain way doesn't mean it is right or natural.
Our past is much much different than our current cultural paradigms, which means that the way we structure our relationships is very limiting and lessens our happiness because it goes directly against our very nature. We "should" be allowed by our partners to sleep with who we want under whatever safety conditions we agree upon. I know that it has hurt me in the past when I've been in a monogamous relationship and met someone else that I like that my heart or pants want to open up to but I wouldn't allow myself to out of guilt and fear because of my current relationship.
Having also been in an open relationship, I can have sex with someone other than my partner and still be fully sexually charged and actually moreso for my girlfriend afterward. Having sex with someone new is a great experience and it is good for us in many ways. It literally recharges our zest for life and our sexuality. All of you that have had sex(positive experiences) know this, how good you feel. It is NOT wrong. It is very helpful however to gain some understanding of how to manage these types of relationships because 21st century humans are only taught how to manage monogamous relationships. There are people out there that teach this.