AITA for considering letting my ex take full custody because I'm completely burned out?

I (34F) am the mother of two amazing children, ages 14 and 12. I love them more than anything, which is why I'm struggling so much with what I'm about to say.

I became a mother at 19 years old. Since then, my entire life has revolved around raising my children and making sure they had what they needed. I never really had the chance to discover who I was as a person outside of being a mom. While other people my age were building careers, traveling, exploring relationships, and figuring themselves out, I was working, parenting, and surviving.

Their father and I have been separated for years, and throughout that time it feels like he has made my life difficult at every turn. Financially, I have carried the majority of the burden of raising our children. While I've been stretching every dollar, sacrificing my own needs, and sometimes even using rent money to cover school expenses, food, clothing, and other necessities for the kids, their father seems to be living comfortably.

Over the years, he has taken trips, purchased new vehicles, and generally enjoyed life while I've struggled just to keep a roof over our heads. There have been times when prioritizing the children's needs meant falling behind on rent and eventually having to move because landlords understandably didn't want a tenant who owed money. Every move has been stressful for both me and the kids.

I don't resent my children for any of this. They are wonderful kids and I would do anything for them. What I resent is feeling like I've had to carry the weight of parenting almost entirely on my own while their father gets to pick and choose when he wants to participate.

The stress has gotten so bad that it's affecting my physical health. I'm constantly exhausted, overwhelmed, and anxious. I feel like I'm drowning. I've spent nearly two decades putting everyone else first and I honestly don't know who I am anymore outside of being someone's mother.

Lately, I've found myself wondering whether I should tell their father to take full custody. Not because I don't love my children or don't want them in my life, but because I am completely burned out. Part of me feels guilty for even thinking it. Another part of me feels like I have nothing left to give. While I'm also thinking if I don't do this they won't have a secure future right now if anything happens to me they inherit nothing

I feel selfish for wanting a chance to finally breathe, rest, and figure out who I am as a person after nearly 14 years of putting everyone else's needs before my own.

Would I be the asshole for telling their father he can take full custody since he refuses to properly share the responsibilities of parenting?