I'm in a similar but not identical situation. My wife has a chronic condition, I have been her carer for 15 years, brought up two children who are now well functioning adults.
Her condition fluctuates sometimes you wouldn't know, some times she has stoke like symptoms and relies on me heavily and requires a wheelchair.
She has previously worked but this was unsustainable.
This causes me a lot of stress and definitely has an cool impact on my health. In my opinion she could manage her condition better and maybe be more capable day to day. I am also aware that she is often in constant pain, cannot sleep and has lost a lot on her life due to illness.
I have had to leave a career I loved and have the daily burden of working full time whilst juggling her care.
I posted on here some time ago about how this was getting me down and that I was tempted to leave and or get a fwb. I wrote this post keeping gender out of it and most replies told me to leave and that my "husband was taking the Mick". I'm still here as her illness is not her fault and it is the illness that causes the problems and stress. Yes she could do more but pretty sure this causes her depression and life is hard for her. This is not her fault.
On here it seems that all men are bastards and all women are saints. Would the advise I was previously given have been different if I had stated that I was the male? I think it probably would have been and that I would then be the bastard abandoning his wife in her time of need.
Being a carer is hard, very hard. I have been in the military and served in conflict zones. Being a carer is more challenging.
I do lose my patience, I do get down and frustrated, I have thought about cheating (but haven't). Overall I keep going as she didn't ask to be ill and I think about how I would wish to be treated should I find my self in a unfortunate position outside of my control.
Maybe look at some carers sites or face to face groups, look at pip and carers allowance.
Make your own moral decisions and be aware that the collective coven on here often provide one side advice.
Maybe something to reflect upon.