Open or not-so-open

Could someone tell me if one could want open-relationship as one-to-one relationship scares?

Lots of people are fine with open/poly relationships. Just depends on the person. You won't know until or unless you talk to the person you're interested in. Don't take it personally if that's not their thing though. BUt I have to ask. Why does a one-on-one relationship scare you? For most people, the far scarier relationship is the open/poly route. So this is intriguing.