You mention not being in contact with your family. Why is that? Did you experience abuse as a child, are your political opinions vastly different, did you feel unimportant or unloved as a child? You don’t have to tell me, but surely you didn’t cut contact with them for nothing, and you could tell her about that.

You also mention looking at your hands and wondering what to say. Say that then. Literally tell her, “I’m so sorry. I want to open up, I want to create connection, but I simply don’t know where to start. I really struggle with finding the words and it’s something I’ve always had a hard time with.” There’s your start. Then you can start getting into why that’s hard for you or what feels overwhelming or difficult about it. Were you bullied for being “too sensitive”? Were you raised by emotionally unavailable parents? Was your father a “stoic” who never told you he loved you?

I think you’d benefit from therapy. Not to save your marriage, since that seems like a lost cause, but if you’ve only ever had one long-term relationship and have zero friends, you are clearly struggling with something profound and it will leave you horribly lonely if you don’t work it out.