My closest friend has stolen my girl, what do I do?

This is so messed up, I met a woman and really fell for her. To me it was perfect, my closest friend always told me she was a gold digger and cheated around with everyone. I never believed him or played into it and never said anything to her. He took her number from my phone and filled her head with the same stuff via txt without me knowing but she believed it all. Now, looking back I can see how he played us off against each other. So I don't know if I should walk away or what? I feel it's too late now and I'm hearing rumours that she's now pregnate to him? So? Any advice? Anyone?