This is all good, I'm glad to hear her behaviors are changing and that you're craving some alone time. Take it! And be upfront with her. "I've spent a lot of time alone this past year. Sometimes I find it helpful and enjoyable, and I don't want to be with people every second. I still want to hang out with you and work on this, but I've gained a lot by being alone as well. I don't want to lose what I've gained."

Or maybe even just, "I think I'm gonna chill at home tonight. See you tomorrow for lunch?"

I think the trick (at least to me) in starting the awkward conversation is to just be bold about it. Just remember it doesn't need to be a conversation - just a statement. Recognize that you are a whole new person now. So you will act differently to her in some ways. If things start going in the direction where you feel you will be intimate in the near future you can simply state, "W, things are different now. Looking back to when we were 25 and dove in without any real discussion to our health I cringe a bit. So now with this new start I'm going to ask that you be tested before we are unprotected".

This question is NOT about OW. It is NOT about specifics or details or asking in any way about OWs health. Stop her and let her know you don't wish to discuss it. This is about you and your request for her clean bill of health.

Have protection available with you for the time before she does so.

A couple scenerios could happen. She could balk. Let her. Any person - ANY person - who balks at someone for this is not someone we should be sleeping with. Immediate permission to pack up and excuse yourself for the evening. I remind myself of this all the time in preparation for this exact about health.

She could come back with the "Well what about you?". I suppose this dependson how it's intended. Is it blame shifting? That's a reason to step out for the night and let her stew in it. No time for temper tantrums. Is it a legit concern of hers? You could offer to go as well (alone or separate). Never hurts anyone for additional clean bill of health.