She's been engaged to every boyfriend she's ever had.
Not that hard to understand.
The insecurity of her illness.
Every day the possibility that the disease will cause her to lose her job, lose her car, lose her home, commit some crime she doesn't remember and wake up in prison. All the nights she's spent in parks, bushes, the beach, her car, because she bought alcohol with her rent money and had nowhere else to go.
There's no wonder she seeks a guarantee.
In blackouts she weeps bitterly, saying, "All I've ever wanted is for someone to say to me, No matter what happens, I will always be there for you."