Sheridan made the announcement on Instagram in a post to promote their front cover of men's magazine DNA with fiance Kurt Roberts.
In the interview, the actor explained they were now comfortable with being "gay" despite not wanting to be labelled.
Sheridan told the magazine: "Now I'm marrying a guy you can call me gay. Whatever! The point is, we're all human and, in my case, labelling put me into a box that felt like a cell."
The 35-year-old proposed to Kurt, who is the general manager of digital lending at the Commonwealth Bank, on stage during the first night of the Adelaide Fringe Festival in March.
"I went out and bought a ring and flew his family to be seated in the audience on the night. He had no idea. It was a really amazing moment," Sheridan said.
In an interview with Stellar Magazine last year, the star revealed they feel a "responsibility" to speak out in an effort to help others who are still "figuring themselves out".
The Adelaide-born star said throughout their school years, their peers assumed they were gay - a label they felt was "misplaced", because at that age, they had never been attracted to the same sex.
"After moving to Sydney to attend NIDA, I finally met a guy who I connected with emotionally, mentally and physically," Sheridan, who had been in love with women before that, explained in the piece.
"I was over the moon – I could finally be what people always wanted me to be, so I told everyone. In return, I was told that if I was anything but straight I'd never find work, and that I needed to hide my new-found love. To add to the confusion, the two mentors who told me this were openly gay themselves; they were earnestly trying to protect me and did indeed have my best interests at heart. That was just the reality."
