I am fairly new to all of this too..my partner is poly and I would consider myself poly-curious. I have tried mongamy and it didn't satisfy me,yet this man I love now has led me to see a side of myself I never would have dreamed of. He accepts me 100% and I him,it is most unusual but immensely satisfying,because I never thought I would find that anywhere! My self confidence is at an all time high..
What has worked for me has been working on different aspects of the relationship individually,initially we had a very strong intellectual connection which then developed into a physical one and now we have found a very deep emotional connection too,its different for everyone but you must tell him how you are feeling and ask him questions if you are unsure. I did alot of reading in the beginning and found this forum to be very enlightening and helpful.
It is natural to feel fear when you don't understand something or don't have the tools to deal with a situation. I still have days where I go 'what the heck am I doing?',but I have no need to seek reassurance that he loves me or cares for me,because he shows it everytime we are together and in our conversations.
A year ago I would have been 'poly-what??' but now my mind is fully open and my emotions engaged like never before.
I'm not suggesting for one moment that you head full steam into a relationship with this man,take your time,explore,talk,ask,read and get to know him as a person,as a friend..this is not for everyone,but by coming here,you have shown you are open to learning..
All the best!