Books on entering a romantic relationship with emotional trauma

As they say, trauma isn’t the bad thing that happened. Trauma is what gets stuck inside you afterwards.

I am looking for books that help us navigate romantic relationships where one or both partners have severe emotional trauma. Any book that helps one empathise with their partner when their trauma response flares up.

I have read some of Alain de Botton's work, but I want a deeper dive into this.

Not looking for generic healing books or relationship books. But specifically for those who deal with navigating emotional trauma in romantic relationships. The what, how, and why of it.

Any recommendations?

Thanks in advance.