I thought like this several years ago, too. But then I've discovered that after having relationships for several years in the row with the same person, I started to miss freedom, which I had when I was single and could go out with anyone without obligations and dramas.
From some point, every time I accidentally read or watched something with the romantic ending like "and they lived long and happily and died in the same day", I started to feel like I wouldn't want such an "ending" for myself. Because in the context of strong and not treatable jealousy, which all these characters usually have, it inevitably implied "and they had sex only with each other until they died". I slowly started to perceive it like a sort of imprisonment, and these thoughts started to depress me.
I know people, who look quite happy with living that way, and I believe that they may really feel comfortable, having sex only with their beloved one and don't need anything else. But I've realised that it doesn't work this way for me.
I don't call a sex with other guy/girl as a "cheating", if the partner knows about it and doesn't feel bad about it. In the same time, I realise that a lot of people just sweep all such a things under the rug, having sex on side, but hiding it and lying to the partner. This is what I still call a "cheating", and I personally think that it is very hurtful thing, because I have (somewhat idealistic) view, that good relationships should be built on trust in any case.
I know, that my opinion on this topic isn't quite popular (for a woman), and it's a bit sad for me, but it's generally ok, cause other people obviously have a right to their own opinion, too. I feel really bad only if people scream on me / humiliate me / insult me in all possible ways / threaten me because of my opinions, as my parents did. But fortunately, they are the only people so far, who did this to me. All other people, I'm communicating with, either don't care at all, or are more-or-less tolerant.
This sad, but I'm not sure how to help it. From what you wrote, maybe the problem is, that you are communicating with the guys most of the time, and it decreases your chances to find a girlfriend. So I'd suggest to visit more places, where are more girls around. But again, since I don't know much about your situation, I'm not sure will it work or not? But at least, you can try.