<human>: Can you give me the gist of the text in a nutshell?

So a little back story, I (f24) live with my fiance (m40) and his mom lives in our home with us. In January she had a stroke which made her very limited in what she could do, but she could get to the bathroom herself and function without much help from us even though she is wheelchair bound. We had people that would come in and bathe her, do her laundry etc. OK fast forward to a few weeks ago, she fell and broke her arm, it's now casted but she also has lost use of her legs, Dr's are saying it's her arthritis, but she could use them before the fall, the xrays of her legs showed nothing wrong with them. Anyways she is 100% dependent on us for everything now, and we both work full time, we have people that are in and out but no one that is actually with her constantly. It wouldn't be so bad but it's like she doesn't want to get better and all she does is cry and get defensive about everything. All of it is wearing me down mentally and idk how much more of it I can take before I start resenting my fiance for putting me through this. I honestly think it would be better for all involved and way safer for her if she was in a nursing home but he doesn't want the guilt that would come along with putting her in one. I love him so much but I don't want to marry him next month and then regret it bc I'll spend years taking care of his mother and being stuck at home constrained bc of her. I don't know what to do, just looking for someone who may have had similar experience or may have some advice.
<bot>: fiance's mother lives with us and requires constant care, it's wearing on me and I've considered calling off the wedding, looking for answers on what I should do.