firstly, huge hugs to you.
it must be so tough in your life right now. i send all my best wishes and energies to support you.
i know the ending of a relationship is a tough thing.....that being said it is harder to keep a relationship working through communication and i personally think that it is even harder with a poly relationship. that being said it can also be extremely rewarding.
i would be really really angry at the man that you are dating. to me it sounds like he is jerking your chain around as nycide said. personally i wouldn't put up with this. if someone cares about you they firstly wouldn't lie about you. i hate to say this but both my partners wouldn't take flack about me from their friends. who he loves isn't their business unless you are somehow abusing him. which i don't' think you are.
if someone loves you they will want to foster your growth and the love you share through honesty and communication. that being said poly isn't for everyone. it sounds like you have had a rough spell in the dating department. not all people are that way. finding the gems are hard
maybe some soul searching is important . is there a pattern that keeps happening . do you choose similar people.to protect youself do you need to have some health boundaries in place with new friends. would you treat others the way you partner is treating you . you don't need to sell yourself short just because you want someone. people should be there all with you . you should be one of their moons and stars.
it also sound to me like you are missing some friends in your life. i will try to send you my face book. i may not be around lots. but i do have a shoulder and am willing to listen.
as to him being dishonest with his friends and other partners to me this is not cool. he is sabotaging your relationship with him. as to sitting him down and having a talk with him that will be tough. i know you can do it.
big loves your way ....part of me wants to smack this dude for treating you this way. no one should treat another this way.