You've been dating since "literally when I knew it was all over." You've been through several relationships.
Take a break. It sounds as if you are still using relationships as bandaids. No relationship will work as long as you use the relationship to self-medicate. Of course you drop the relationship when your partner wants more from you. No one wants cough medicine to want something in return.
As for fertility, perhaps you might want to freeze some eggs to preserve your options.
