When I first started reading your thread, I was thinking I might be telling you, that you probably weren`t poly, and not to feel bad about it. I`ve been there done that. I'm rather an expert, on wasting a lot of time, trying to adapt to something that didin`t work for me.
However, as I read more and more, I agree with MindfulAgony. I don`t think your core problem is with 'poly'.
From what I am reading, you are frustrated with being alone, frustrated with doing things alone. You are frustrated with Dating
and the process of it, not so much the poly part. I don`t think you can know if you are 'poly' until you have a chance to express feelings for more then one person at a time.
This,..has nothing to do with your partner.
Whatever issues you have with your partner, could be tainting your ability to date objectively. If you feel less confidence, and overall 'less' this would be happening in a mono relationship that has taken a turn for the worse too. Many times, people break off a relationship, and don`t date for awhile. They are not 'relationship material' , until they feel healthy and strong again.
Footnote : For the love of all things natural and sweet, do NOT go to Pick-Up Artist sites. That method, is the WRONG way to catch a woman's attention. Nevermind the type of women that fall for this shit, as they are just going to be a headache further down the road. If you really want something that easily swayed, buy a dog, and tie a porkchop to yourself. Otherwise, working on feeling good about yourself, and once you do, you`ll draw others to yourself naturally.