Traveling with your wife ... and your need to work on a flight are personal choices.
This person traveling with oxygen may NOT have been traveling to LAS for pleasure .. may have been going home after hospital stay or going to a hospital for surgery .. or for some other reason that you have no idea of. Yea they could have been going to gamble and play .. but I (and you) should care less!
This person flying with oxygen may be a frequent flier .. or maybe not. Does it really matter that you fly more than they do?
In any case, how long was the flight? DFW-LAS or ORD-LAS? A couple hours out of your life should not harm you that much. A couple hours out of the person traveling with oxgen may mean a great deal to them (a last visit with the Grandchildren or something).
Yes . I think you are being a jerk.
If pax want to change seats with me just to sit with their spouse .. I change aisle for aisle. PERIOD. I do not swap aisle for window (or window bulkhead).
However, when the FA requests I do something to accomodate a person traveling with a disability .. I would certainly do it. Not because the FA has asked .. but because the person with the disability has the COURAGE to travel.
I had major surgery this year and my travel was cut way back. I have had difficulty walking distances due to the chemo therapy (low hemoglobin levels). If I need HELP when traveling I ask for it (I have not had to request a wheelchair yet but that is something I would do if I had the need .. it just takes me longer to get to the gate!). My 'problem' is not immediately obvious as someone requiring oxygen (or a Guide Dog or a wheelchair or ...). If there is a medical reason for seating changes .. I think it only correct to accomodate the requestor. If its to sit with their spouse or get a better FEBO seat or be able to work on the plane .. I do not accomodate them.
I admire people with the COURAGE to travel when their body says it might be wise not to. I have a close friend who took his family to Europe on Holiday and his father had to be medivac'd home because of seizures .. but he and the family had the COURAGE to travel. Its a memory that will last the family a long time .. but they did it!
I was on a flight BDA-JFK where a husband/wife and two kids were trying to arrange seating in First so the husband could get a bulkhead aisle seat. He had been in BDA on business and the prior afternoon had taken the family to the beach on rented mopeds. The husband had a shattered leg/knee from the accident and was flying home for immediate surgery. They had to use the catering truck at 1R to bring the guy onboard. He ended up taking three seats in coach to keep his leg elevated .. and the rest of the family sat there with him (tho they were originally all in First). As I recall the coach pax that were displaced by this were moved to open First seats.
Someday YOU may be that person with the medical issue in need of a favour. You never know what will happen in this life.