Wow, bizzybee, I have soooo been there with the waking up in the middle of the night, thoughts going 'round and 'round. Aggravated/frustrated/exasperated. With both him and myself. (Fortunately, I have the good thoughts about him too, but the middle of the night ones? Not so much. ).

Anyway, like you, I don't know to express a lot of it. And therein lies Problem Number One. The biggie. When you say he's not done anything different than usual, this is true! Here's a guess how it went. Maybe it bothered you a bit the first time, but you didn't say anything because maybe it seems such a little thing that it doesn't seem worth speaking up over. Then another time and so on. And you start to notice that it really is something that bothers you. Yet it has become harder and harder to say something because, well, it seems so weird to say something after so long of not saying something. And they will be perplexed why you didn't bring it up before seeing how they're not a mindreader. And maybe there are other things that gnaw at you in these brooding sessions. Bet they followed this pattern too. Point is, in keeping it in, it really does build up and get mixed into one big ball of intertwined confusion and frustration. And guess who knows it? Your subconscious. Who keeps waking you up to deal with it.

Except it goes nowhere but 'round and 'round. Again, because of not speaking up. It has nowhere else to go.

You are right in saying that it's not good to suddenly dredge up the past in bringing it up. They say that is a bad way to go, because it diverts focus from the current thing. The thing that is actually at hand that can be worked on. The rest is water under the bridge.

Why the intrusive thoughts now? Probably because they've been building and with an event like your brother's wedding coming up, it triggers additional pressure on what you have already been worked up over. Hence, yeah, now.

I do think that we have other things in common. I wouldn't put them down to BP, but to the fact that there are a lot of people just in general who have trouble bringing things up/having potentially difficult discussions/taking awhile to put a finger on what it really is that is bugging them...

As far as how to approach. Anika's right that a T could be helpful. My personal approach is to write things down (yup, in the middle of the night ) as I solidify what it really is that is bugging me. To clear the clutter. Distill it to where I can see my point coherently. And just the release of putting it out of my head and onto paper helps (doesn't cure, helps). And to decide where I want to start with it. Start small, work up. Barraging someone inevitably lead to some serious defensiveness. When things are calm or they seem in a reflective/receptive place, I'll agree that they have such a good idea and try to work in one of my concerns. Into their plan. Takes forever, yeah. And a flipping lot of patience. Another way is that sometimes he will notice something's bothering me and wants me to say what. Like you, I find this difficult, but I try. Almost inevitably I remind him that X number of decades of not being able to speak up is a hard habit to break, but that I will try. And this is true. Somehow it strikes me that one person conceding what is true and difficult for them can help the other person concede something that is a problem in their behavior. Surely more so than one person launching on the other with a laundry list, lol! Oh, and try to speak from "I" statements. How something makes you feel, instead of, "You always do this! You always do that! You are such a jerk!!" Sounds soooo obvious this approach would be ineffective, yet it's practically universal(!)

(p.s. Anika, I don't see this as a BPD thing... there doesn't seem to be any idealization/suddenly devaluation. It sounds (to me anyway) to be about all the little things that build up over time in any relationship and how, if left unsaid, find a way to work themselves into our subconscious, grawing slowly over time.)

Ooops, novel! Sorry! Answer to your thread title: IMO, yes, anxiety. From little built-up things that your mind isn't letting you ignore anymore. Good luck and keep us posted!