srry for the tldr. hoping a few here will have patience to read thru . tia.

my wife came out from the bedroom last Saturday morning (8 days ago) and told me to go without her to our weekend home - she'd catch up later. she wasn't feeling well - sniffles and congestion.

I have been diagnosed in the last couple weeks with a fairly significant autoimmune condition for which I have NOT started treatment. (not sure what the doc has planned yet).

I basically bolted from the house and have been at the weekend home since then (8 days now). My wife stayed home - and was hesitant to get tested - so she didn't. I got tested last Thursday (6 days after leaving my wife at home). the test was a simple throat swab and I got my results today (8 days after leaving home)...it was negative (yay!)

my wife reconsidered her decision re: testing and got herself tested yesterday (7 days after symptoms started) - results are positive (ssss!). I'm going to get tested again early tomorrow morning. I'm wondering if my test from Thursday could've perhaps been a false-negative. I have zero covid symptoms (I actually feel great - except my wife is sick at home and I can't be there to help her. I call her three times a day, as does our adult daughter who lives close by). My wife's symptoms are starting to wane. she is by no means suffering except loneliness.

what I'm hoping to get here is advice on how to proceed. If my test tomorrow comes back negative on say, Tuesday (11 days after exposure), should I go home and expose myself to my wife? i.e. considering my autoimmune situation and the length of time since her symptoms started

...I'll be contacting my rheumatologist asap if my next test is positive

CDC

Basic CDC guidance for her is that she can be around others at this point:

• 10 days since symptoms first appeared and
• 24 hours with no fever without the use of fever-reducing medications and
• Other symptoms of COVID-19 are improving*

So, if her symptoms first appeared last Saturday, you start counting from that day.
Your last exposure to her was last Saturday, so you're still within the 14 day quarantine period.

It's quite possible/likely that you didn't catch it from her and your original negative test is accurate, so I personally (not a doctor) wouldn't suggest getting tested again unless you develop symptoms.

All that being said, if it were me, I'd isolate until at least Monday when I could get advice from my specialist.

Best wishes to you and your wife