I am not sure if there is a “true ” safe way. I know a lot of us have been in the same place.
I feel that if the relationship is important, then seeking marriage counseling is the best choice.
I had 28yrs with my SO, and we have 4 children between us.
But when I came out last summer, she said it was over. It was a deal breaker.
We have been working to keep our friendship and that has been a very slow process.
I also know that it can cause more harm than good to keep things bottled up.
I hope you can find a way to balance both the relationship and the lady within.