Curious to know how this co-worker told everyone in the office about you being gay? Did they send an email out or have a meeting with all the other co-workers to let them know or did they tell one or two people and the word spread? Did this co-worker do it in a mean way or did it just come up in conversation?  The last thing you want to do is give up and quit. Be Proud of who you are and anyone that mis-treats anyone, especially now in 2019, differently for the way they choose to live their lives are just plain ignorant. Not knowing all the details I would at the very least have a cordial conversation with the person who told the other employees and let him know how it made you feel than go from there.