The Amastacia was not particularly a hussy before she joined the heroes of the last age. She grew up in a monastery in what is know Citadel Refuge, tutored by monks of an order known as the Lighted Path. They had rejected the gods of the day (Aon, Oberon, etc.) as actual Gods, and much of their philosophy clearly influenced the way that she and the Apecto gave form to the current Church of the Light.
However, it is well documented that the Amastacia preferred to be naked (or nearly so) in all but the most dangerous conditions (such as combat) and thus while the record would suggest that she was faithful to Link Woodshadow, she was apparently not shy about letting others see the "goods."
If she had previous lovers, they are not mentioned in anything written by the woman herself, or in anythiong written about her. However, as her life is not well documented before the age of 19, anything is possible.
As for babies and combat, the Amastacia did not write extensively on the subject, as it was unlikely to be a concern for an average follower. That being said, it is well known that her first child was with Link when the Amastacia was killed - and he was, if not in active combat, at least participating in some aspect of the war against the Bluestar. While Caer Melyn was far from the front, it was still a dangerous place in her time. Though her second child was assumed to have been killed in the combat that took the Amastacia's life (you now know that's not true) the doctrine that emerged after her death did not condemn the placement of the child.
In short, during a war, you do the best you can. No where is really safe in a place where teleporting is possible, so you do your best, and if something goes wrong, you pray to the Light to help you deliver justice against those who would harm a child. The Woodshadowan addendum to that would be something along the lines of "when you're done praying, you go deliver justice yourself."
