It could be a situation or actual objects. Sometimes it's a person's behaviour, which actually “re-trigger” an emotional response of similar intensity to the original traumatic incident.
People pleasing can be extremely exhausting. Not only does it run a poor girl ragged, but it often seeps into and destroys the foundation of any relationship it enters.
There's nothing quite like walking into an empty space and having to start the nesting process all over again to bring the harsh realities of divorce to the surface.