Friends - Season 4 Episode 21 : The One with the Invitation
Ross and Emily discuss who to invite to their wedding. He wants to invite Rachel while Emily thinks it's odd. Ross sends her an invitation anyway. The gang receives their invitations, all except for Chandler, as they reminisce about Ross and Rachel's up-and-down relationship. However, a very pregnant Phoebe can't go. Rachel wrestles with the idea of going to the wedding and after deciding against it, breaks down and cries on Monica's shoulder.