Spice things up..??

I'm feeling lately like my SO and I have a boring bedroom life... He has some kinky fantasies that I'm not sure I want to entertain (two guys & a girl) but am looking for something to spice things up without going past my comfort level... Which I guess I'm not really sure what that is at this point... So all suggestions are helpful... Willing to ponder all ideas... Ready! Set! Go..!