While Barton's waiting for Coulson to return, Steve Rogers confides to Barton that he's gay, and Barton becomes Rogers's confidante and eventually his very patient boyfriend as Rogers struggles to accept himself. This all happens with Coulson's knowledge and approval, and when Coulson returns, he and Barton work together to help Rogers become comfortable with the idea of a gay triad.
Thank you in advance for any help you can offer.
EDIT: Found! Thanks again!