I chose the latter.

I have always been glad I reached that determination without the aid of any impulse outside of myself; for events soon happened which again drove all faith in Mary from my heart forever.

Those events would have forced me to abandon my trust in her; but mind you, I took my good resolve from inclination rather than necessity before I learned of Mary's perfidy.
The events of the night had exhausted Dorothy, and she was confined to her bed by illness for the first time in her life.

She believed that she was dying, and she did not want to live.

I did not go to her apartments.