Go read River's Emotions Post on the general board and see if you can work through your issues.
That's my first piece of advice.
Why are you feeling this way?
You established that it's NOT HER. That's a great step-most people blame first then realize it's themself (hell they even do that in the new tinkerbell movie!) but insecurity, fear, need to control, these are almost always caused by something internal.
So what is going on in there? What is up in yourself that is causing this reaction?
Until you figure all of that out-you can't resolve what the solution is.
If you already know you CAN do poly (as you did before and allegedly didn't stop because you HAD to) then why suddenly are you afraid of it?
"Love As Thou Wilt"