Feeling burnt out and need a sanity check
So I (32m) have a partner (31f) who I have been with for 5 years. They don't have much capacity and have a fair amount of mental health struggles. The support is typically mostly me supporting them and I don't receive too much in return as they struggle to care for themselves, let alone someone else. I generally don't mind it, but am starting to feel a lot of compassion fatigue. This is exasperated by the fact that in December my father died, and I didn't receive any support as I went through everything, but I continued to support them. And then in February I was hit by a car and broke my back, and it took them a week to visit me (we had 2 scheduled date nights before they came, so it wasn't that they were too busy)
Recently they have developed a crush on someone, and have been going out of their way to see them as much as possible, and putting in effort that they're seemingly unwilling or unable to put in for me.
I've spoken to them about this, but nothing has really changed yet (I'm only 4 days out from talking about it, and I know I need to be patient and give time)
I'm having a difficult time moving past these feelings, and figuring out what is reasonable. I'm not going to ask them to stop pursuing their crush, but I have worries about seeing them put effort into either a potential or new relationship, while feeling neglected.