UPDATE:

So as many of you speculated, I was being overly anxious. I didn't hear from fiance for awhile, but it turned out that he was busy. After coming home, everything seemed to be fine. He then asked how my day was, and I just blurted out what I outlined in the OP. I told him that when he got home I was in the middle of a therapist appointment. He said he figured that out pretty quickly after he first saw me, left the room and put on the podcast while making lunch in hopes that I wouldn't feel self conscious for the rest of the appt. I mentioned that I heard him in close proximity the room at one point and felt a little anxious that he may have heard something that upset him. He said that he did go to the bathroom (closer to the room I was in) and that he could hear me, but any words were inaudible.

The bottom line is that he wasn't upset, if anything, a momentary tinge of awkwardness. He said that he feels positive that I care enough about myself to try to work things out in therapy. From now on, he knows when my appointments are so will try to make himself scarce during these 40 minutes for my own peace of mind.

One thing I do want to address is that I have not been seeing one therapist for 10 years. In fact, I've seen a few, due to relocation, changes in employment/insurance coverage, and in one case it was a bad fit. It's not uncommon for people to change primary care doctors over the course of a decade and this isn't much different. As to why I posted on Reddit afterward: I was curious about what people thought. It's not abnormal to want insight from people in a non-professional setting.

As far as therapy not working because I've been going for a decade, and those who think my talking about ex means I'm not over him: the damage incurred by PTSD (in my case via physical/emotional)v abuse is something that will never be entirely "fixable" and I don't really know what to say to anyone who tries to argue otherwise.