Cancer caregiver burnout

I'm in search of a long-term listener regarding caregiver burnout and the health effects of burnout in general. I'm recovering from a long term relationship ending due to a different reason but I feel like I was so ready to quit because I was burnt out before he got diagnosed with lymphoma. I left a few days before he found out he has cancer again and I feel stuck. While I know how he treated me wasn't okay I still struggle with guilt and feelings like I'm abandoning him since he doesn't have anyone else who can care for him like he needs. I probably became codependent on being needed and did more for him than I should have. It's been just me and him the last five years and I'm feeling from the transition. I want to continue my education into nursing but with his diagnosis and oncoming treatment I feel myself digging my heels in and procrastinating.