Advice for an alternative tomboy for a wedding outfit

This is my usual style. I'm very basic and only wear black. I also feel very uncomfortable with dresses, but I have a wedding this weekend and the people there are more on the traditional, religious side of life. I know that they have no issues with me wearing all black, but I wanted to wear a suit and with THAT they take issue :'] Any tips for how I can find a nice middle ground?