A wedding date with his bestie

Soooo... my bf and I have been dating for two years in November. He has had a lady friend who I have never met from his home town in Philadelphia (we live in Texas). Recently he told me that she wanted him to attend her sisters wedding with her. She is a bridesmaid in this wedding and gets a plus one obviously, but I can't shake the jealousy a bit that he wouldn't ask to bring me. My bf has never given me a reason not to trust him ... Am I just being ridiculous? ):