Just that really. For me it was years of doing everything on my own, him not caring about when I'm ill, or heavily pregnant. Him not having any goals or ambitions in life, not being able to hold down a job. Would literally work for a few months, then he would get sacked or quit.
Then there's the same arguments over and over again, it just worn me out. And there's the abuse, controlling/bullying behaviour.
I just stopped loving him, didn't want to kiss or have sex with him. I didn't find him attractive anymore, it took me awhile to realise I didn't love him anymore.