You would be the one to know if you're poly or afraid of commitment. If you're afraid of commitment, being poly won't help (you need to commit to even more people!)
However, if your feeling of being trapped is due to "not being allowed" to have someone else, it could be that poly (or swinging) would be suited to you, or nonmonogamy in general, and I would suggest looking for a partner who knows and understands that.
I think the easiest way to figure it out would be to wonder if you've ever been in love with more than one person. Think about relationships, too, what feels best for you, being with one person at a time and ending the relationship to start a new one when it's too committed, or having several partners at once, or one with the option to have another one?
Would you be fine with just one relationship if it wasn't as committed?
Also, what would you qualify as committed? (Did I mention the word committed? :P) Is it the length of the relationship, or just a feeling, or is it more concrete things such as moving together, making plans for the future, etc...
I don't think there is a way for us to know if you are poly, and giving you tips might be hard because people don't always realise it in the same way or for the same reasons. On top of that, there are several types of poly, as well, so you might think that one doesn't work for you, and yet be poly, just better suited for another type.
Here are some example of types to help: You can have a single primary (person you have a serious relationship with) and other relationships that are less "important" for various reasons (less emotional involvement, less time spent with them, no plans together, etc). You can have several primaries, and they could be involved together, too (for instance a triad). You could have no primaries at all, only secondaries. You could be in a polyfi relationship, meaning you have several partners but you don't look for other people (similar to traditional monogamy but with more than one person).
Whichever works for you, there are mono equivalents for a lot of them (the first one could be equated to a fusional mono relationship. Another would be the equivalent to dating but not "planting roots", simply with more than one partner at a time...)