@ThatOneEmoChick007 Glad to answer your question. I decided for there not to be any birth control in this story as I thought it would make the intimacy less impactful. If the characters could just slip on a condom or take a birth control pill, the sex loses a lot of its meaning and mystique.
Without these safeguards there's risk and consequences. It makes the characters have to weigh pleasure and intimacy against the chance of pregnancy. They can't just jump in the sack, they have to be mindful. May and Drew's story is an excellent example of this.
Additionally, for Serena, she wouldn't be sad if she happened to conceive Ash's child, even accidentally. Its one of the reasons she's perfectly okay with sex.
I'm glad you like the story. Thanks for the question.