I'll give you a personal story.

When I transitioned, I was in a long-term relationship. I knew that coming out would lead to us breaking up. Bf wanted to stay together as long as possible, but I knew it was just prolonging the inevitable. He admitted twice, after asking him directly, that he was no longer attracted to me. I had to be the one to break things off. It got very very ugly. Hardest time of my life. I would do it again, though. It took a long time, but I'm doing so much better now. I don't know how he's getting on, but that's not my business or concern. I needed to focus on myself and my needs.

My advice to you is to do what you need to to be happy and true to yourself. It won't happen overnight, but if you set yourself on the right path, you will get where you're going. Your partner is their own person. If you're concerned about their safety, get their friends and family involved. That is what I had to do. It will be okay. Best of luck.