The Girl in the Corner by Amanda Prowse

Rae-Valentine and Howard were childhood sweethearts. They’ve shared twenty-five peaceful years since they were brought together by Dolly, Howard’s larger-than-life sister. But now, on the night of their wedding anniversary, Howard reveals a shocking betrayal that leaves Rae reeling.
Heartbroken, she takes Dolly on her would-be anniversary trip to Antigua and the two women drink and dance and talk like they haven’t in years. But in the break from real life, Rae realises her choices have always been made for her, and suddenly she’s questioning not only her fragile marriage but also her one-sided friendships. Is she really the pushover everyone else sees?
When Howard comes looking for reconciliation, Rae has a choice to make: keep the peace, as she always has, or put herself first for once and find out who she really is.