Reddit mentions of You Were the First

From the situation you describe, it sounds highly likely that you will be offered this new baby when the time comes.

I'd advise you to begin preparing yourselves and your toddler. Read books about new babies (and choose them with particular care! I'd avoid books depicting pregnant mom and/or birth)

One book that you could read together even if you didn't end up getting another sibling, is a beautiful children's picture book called "You Were the First" and it talks about how your child was the first to teach you how to be parents. It's unspecific about birth so it applies to a wide variety and fits for kids who were adopted.

Near the end of the book (that may make you tear up, it's very touching) is a line about, "Some day, there may be another... but you will always be the first" And again, it doesn't go into details about whether this "another" will be from pregnancy or adoption or foster or what.

"You Were the First" is a good one. I like it because it really focuses on the child you're reading to, as some other books focus on the child to come.

We're getting my 3 year old these books : https://www.amazon.com/You-Were-First-Patricia-MacLachlan/dp/0316185337. https://www.amazon.com/Big-Brother-Caroline-Jayne-Church/dp/0545688868/ref=pd_bxgy_14_img_2?_encoding=UTF8&pd_rd_i=0545688868&pd_rd_r=e463bca1-e694-11e8-8744-d97de4b97d5c&pd_rd_w=MyqwB&pd_rd_wg=EpXxx&pf_rd_i=desktop-dp-sims&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=6725dbd6-9917-451d-beba-16af7874e407&pf_rd_r=5PQB7WKGEGAZ1ARQFR0K&pf_rd_s=desktop-dp-sims&pf_rd_t=40701&psc=1&refRID=5PQB7WKGEGAZ1ARQFR0K