"Its genetic".
I mean, don't worry too much for your way of living. I am pretty much like you too, maybe not as extreme, but with now 53 years I prefer my time being spend alone, and never needed it to have people around and a "rich social life". Actually, needing to care for too many social contacts is work, is annoying. Few, but better, is my parole. Peopel are different. The virus did not bother me, I thought about it, implemennted some cautionary and I say reasonable measures from every early on: I wore masks when entering supermarkets earlier than most other people, and I tried some nutrition tricks to beef up my immune system's strength, I wash my hands for a inute when comign back home and do so again after I have unpacked bags and storeed everythign away, and I do what I did beforee anway: I stayed for myself an kept distance to others when being outdoor. And I bit others away if they got too close.
Peop0le are different, and I do not necessarily need it to leave the house at leats once every day. If you are like this too, fine, everything is okay.
As a submariner you have further adopted to this lifestyle, i assume. And maybe this was what attracted you to submarines in the first.
Now, you said "anxiety". I do not know whether that is related to the virus threat, or due to having left your home, the roof over your head missing, being in the wide open. I would - hesitently - consider a
very small chance for you being vulnerable to agoraphobia, but that is really just a chance, and if you do nature photography, then you must have gotten used to being outdoors a lot in scotland. If you never had a feeling of anxiety back then, then forget about agoraphobia.
In open outside places, the risk of catching the virus is very, very, very low if people are not within 10m or so, and evena bicycle or jogger passing you can infect you - but most likely will not. Having somebody standing close by at a traffic light is something that could trigger you stepping away a few steps, and crowds I would evade anyway, and entering shops I do only with selfprotecting FFP2/3 masks, and I limit the shopping days a smuch as I cna and cut short the time I spend indoors of shops. Sometimes I mind the wind, if I cannot apovid haviong people nearby, but not too much. But you walking with your wife in lonely open nature - don't bother with feeling worried! The only risk around is - your wife.
Social distancing, not by 2m but by 10m where possible, should ease you of any further anxciety due to the virus. Stay out od enclosed compartments, to avoid aerosols. All that you did not tlak of, you said your anxiety is when leavign the house and beign outdoors. No risk there I see. Relax.