(I/he/she) used to forget, (I/he/she) was forgetting
Miraba cómo daba vueltas y así me olvidaba de todo.
I watched it spin around and that's how I forgot about everything.
— Durante la tormenta (2018)
Olvidaba que la sirvienta tiene fiesta.
I forgot that the maid is having a party.
— Perdición (1944)
Tom estaba tan cargado de trabajo que se olvidaba comer.
Tom was so busy with work that he forgot to eat.