My family was Incredibly supportive which was surprising considering their leanings.
Mom reaction - Told her in 1996. She tried to steal my thunder and, in turn, told me of her same sex relationship with a woman of 7 years. I knew in the back of my mind that her 'roommate' of 7 years was more than a friend after she divorced my father. I mean, her roommate was a captain in the army and the captain of their softball team.
We cried for a hot minute and it was clearly a non-issue. However, my mom is back to men, it was a phase.
Dad and step mom reaction - 'Whoa that's not what you hope to hear, but we love you regardless.' First comment from the phone call where I told them I needed them to sign a power of attorney naming my partner and I as the one in control of certain things. They signed it and sent it back.
Grandparent's reaction - Seemingly unphased. Christmas cards addressed both me and my partner ever since.
3 Brothers - "Yeah, and?"
Nobody else really matters.
Things have been good ever since.