Trauma is mostly believed to be caused by a singular "big" event. Like something big that involved severe abuse or neglect.
When I started my practice, I noticed a pattern with people who had 'normal' or 'supportive' families, yet they struggled with severe anxiety or depression. Many were high achievers yet functional addicts. They found themselves in toxic relationship patterns. And they were confused why they felt 'stuck.'
Trauma is any event where people are denied their authentic nature as children, not being heard and are left to cope with the emotions without guidance in processing them.
THAT is where you learn to betray yourself for love. THAT is where you learn that who you are is not acceptable. The ego comes in to create a sense of self-based on the subconscious desires of a parent. You start to look for external approval because you have lost a sense of connection to self. So you seek relationships that mirror your earliest childhood experiences. What is familiar feels safe, even it IS unsafe. You choose partners and situations where your reality continues to be denied.
Your path to healing begins once you understand that all of your behaviours, patterns, thoughts, and beliefs are simply your conditioning. Those are not who you are; those are a reflection of your past. Ways learned to cope.
What you learn can be unlearned.