Five Winters by Kitty Johnson

A bighearted novel about motherhood, friendship, moving on, and love of all kinds.
Ever since Beth Bailey was a girl, she's been in love with her best friend's older brother, Mark. She's continued to hold out hope that maybe, someday, he'll love her back. But now Beth is thirty-five years old, and on the day of Mark's wedding to another woman, she finally accepts the wake-up call she needs to move on.
Beth's dream of marrying her first love may be over, but her other biggest desire is still within reach: becoming a mother. Having lost her own parents very young, there's nothing Beth wants more in life, and nothing she'll stop at to make her wish come true.
Over the course of five years, and with unexpected twists along the way, Beth will come to startling realisations about family, friendship, the meaning of love, and most importantly, herself on the winding path to happiness and, she hopes, to motherhood.