The protagonist in my first attempt at a novel was a lesbian. However, the story wasn't about her being gay, rather her struggle to gain her mother's acceptance was the underlying subplot, all while her best friend's wedding unfolded into a complete disaster.
I shelved it after chapter five simply because I had no clue with how to move forward. It got to a point where I couldn't write anymore because it didn't feel like my story. I think if you're going to write a gay character, especially a protagonist, you need to understand the struggle itself and not make attempts at including the character just to be all inclusive and risk exacerbating stereotypes, which would not have been my intent.
I began to question myself as a fiction writer. Would I be able to write from the perspective of a racist character, or one of royalty? I could make it up, but how convincing would I be and how effective the story? I found myself wanting to explore and write about things I don't know, rather than write about what I know.
When I got to chapter five and started developing the mother/daughter relationship, I discovered the story wasn't about my protagonist needing acceptance; it was about a daughter helplessly struggling for her mother's love and guidance. If you take the fact that the protagonist is gay completely out of the picture, this scenario could apply to anyone. So then I had to ask myself this question. Why did I make my character a lesbian?

You're welcome. That's what we want to say at the end of our stories. When people finally get it, the just and the righteous, when all prejudices have been lifted, when your inner critics have been silenced in your minds, and when you see your fellow humans as yourselves and you cry those tears of joy, know it is our intent to educate.
Why do you want to write the story you've chosen? What drives you? Is there a point you want to make with your story? If there is, let it be genuine, so that it is real and not gratuitous.