spent her life underworld
Actually Persophone spends 4 months in the underworld, due to her eating the pomegranate seeds and the rest with her mother Demeter.
In Hades for 3 months and with the Gods on Olympus for the other 9.
With her mother Demeter.
Persephone spends the three months of winter in the Underworld with Hades.
It depends on the season and which months.
The Underworld with Hades, her husband.
3 months
On Earth or Olympus with her mother Demeter.
3 to 4 months
because she was bored
This will depend on the species. For instance, the average gestation of a hog is 3 months, 3 weeks, 3 days (113 days) but the average gestation for an elephant is 22 months.
You should spend what you are comfortable with and what fits for you and your future wife. Discuss it with her if you think it is appropriate.
She spent all six moths in the underworld. But have you ever forgotten to water a plant. it takes time for it to die. same concept.