I find it strange that your therapist would raise this as an issue and connect it to your dress. Maybe I'm off the mark, but it seems like this is something that you should initiate when you are ready, and if you were ready you'd be bringing it up first, not him.

If that happened to me, if he brought up the way I dress and wanted to work on helping me enjoy sex more with my husband based on my way of dressing, I'd totally freak out.

I don't know. I guess I'm in the minority here but it just seems insensitive to me. He knows your issues, and pushes this. It feels off, but maybe I'm missing some part of it.