Triggers are something, anything (could be an object, date, remark or an event) that take me back in time, they are a reminder of how I felt at a certain time, they spark a memory of past events, some positive (looking at photos of the birth of your first child) some negative (anything
that reminds me of the time when my wayward husband was... wayward)
Some are unpredictable and some avoidable. All you can do is avoid those you can and hang on tight for those you can't and hope like hell your WH supports you through them with understanding and compassion.
To help explain I'll give an example of a non-infidelity trigger I had today at work.
One of the girls was talking about looking forward to going to a concert, when I asked who's the performer, she said "Pink"... Whammo! I was grieveing for my late father like it was yesterday. I went silent and turned away no longer able to be part of the conversation because I was working hard on controlling my emotions, trying not to cry in front of everyone.
You see, I had tickets to a Pink concert once. I was planning on going with my adult daughter, we were both very excited about it. The day of the concert turned out to be the day of my fathers funeral. Needless to say, we were in no fit state to go and gave our tickets away.
To this day, when anyone mentions a Pink concert I am immmediately transported (emotionally) back to grieving for my father and all the emotions I felt that day. The loss, the heartbreak, the devastation... the pain.
That's a trigger.
Today it lasted just a few minutes and I recovered. My father passed away over 5 years ago but I felt as bad, momentarily, as though it had just happened.
That's what a trigger does, they transport me in time.
I still can't listen to or watch Pink and I really like her music... but it's just too hard for me. Her music is now irrationally linked with such sadness for me. My BFF asked me the next time Pink was in the country to attend a concert, I couldn't. The mere thought of it was too difficult for me and I knew the concert would be joyless for me. She kindly bought me a DVD of Pink in concert to make me feel better because I'd missed out again on seeing her... it's still in it's wrapping, I have not yet been able to watch it.
Messed up though it may be, Pink is now a painful reminder of a day in my life I never want to remember. How can this be? It's not like my father can die again. I have no fear of having to relive that day. He was nearly 92, he'd lived a long, full life with a family that adored him and at the end it was a blessing that he went... but Pink still causes me pain. Go figure.
Triggers can be irrational and often unexplainable.
IMO a WS doesn't have to understand them, just know you will have them. If something is identified as a trigger and can be avoided, then they should avoid it... but if not they should do whatever they can to help their BS through them.