AIO: Major marriage issue while our dog is dying

(throw away account)

My wife and I are having a major disagreement about her upcoming "work" vacation/trip, our dying dog, and we're both livid. We're barely speaking to each other.

Our current routine has centered around caring for our 16 y/o dog whose health is rapidly declining. We've been married 15 years, no kids, and he's basically our child. We both love him dearly and are pretty devastated about this long, slow process of dying. His time is very limited, if not being past time to say goodbye.

Meanwhile my wife booked her annual work boondoggle/conference/vacation to a major fun city a few months ago even though I asked her then to reconsider or plan for canceling. This trip is next week, and she's adamant about going. She is the boss at her company so answers to no-one and cannot be fired for changing plans.

I told her I was livid and in disbelief she's still going on vacation at such a difficult and critical time for us. This would leave me alone for a week to care for the cats, the household, and myself (bipolar); spend hours per day trying to get our dog to eat; pill the dog twice a day; commute back from work (25 mins) quickly over lunch to take him out since he's incontinent; get up at 2am briefly every night to take him out; get home early from work to take him out; take care of her chickens while she's gone; and somehow not lose my full-time job (in-office) which is our main income and insurance source. His eating is the hardest part: it consumes all of our free time since he demands a plethora of changing options and fresh-cooked food on the spot just to keep him alive, and he's still losing weight fast.

We have been rotating these daily and nightly duties for weeks and it's been working / livable for us.

When discussing canceling her trip she said "no way". She's frustrated and feels like she's not allowed to live her life, that she gets punished by me since I'm cold to her when she's often absent during difficult moments, that I need to support her because she's supported me, and "god-forbid I do something for myself". For context she willingly does all of our cooking, cleaning, laundry, and shopping (she adamantly doesn't want my help), and has helped me survive my mental disorder, so I appreciate the load she's under.

We discussed putting our dog to sleep prior to her trip and both agree we're not ready for that.

I told her it will be a something of a miracle if our dog survives through next week or I don't lose my job due to the amount of hookey I need to play.

I also told her I would never, ever leave her for more than a day under these circumstances unless we were 100% in agreement, so what she's doing blows my mind.

I want to tell her that if he dies while she's gone and he and I go through that process alone, our marriage may not recover. I'll have lost trust and faith in her. I've been biting my tongue on that one.

Again, we're barely speaking to each other.

Am I Overreacting?