Struggling with bringing up insecurities in my relationship.

Good communication is key to any relationship but how we deliver that communication and when, is just as important as the content. Our body language, tone of voice, the time we pick to communicate are all important. Using 'I' statements is helpful, 'I feel,' 'I want to express,' 'I would like to say', rather than you make me feel, you do this, you do that. 

Communicating when we are highly emotional will affect our delivery and often we do not convey the message we want to. Taking time out to consider our emotions and how and when is best to communicate is part of the healthy process of communication.

Insecurities provoke anxiety, we need to challenge how we can work through our emotions to be constructive and helpful for us and our relationships.

Consider our emotions; an internal structured reflection is beneficial before we communicate a sensitive issue.  Check what thoughts are running though our minds at the time of that emotion. Ask ourselves are these thoughts rational, logical or helpful?  What thoughts provoke this emotion?  We think we attach our emotions to an event but it's what we are telling ourselves about the event that provokes our emotions and impacts our behavior.

Understanding our opinions/beliefs about an event/situation also helps us to understand our emotional responses. 

We all have negative emotions/reactions, it's part of being a human being.  The key is to determine if these are healthy negative or unhealthy negative emotions.

If they are healthy negative emotions we can learn to understand them in the context of a situation and think and behave in a way that will be constructive/helpful to us and our relationships.

If they are unhealthy negative emotions we will be reactionary, out of context and think and behave in a way that is unconstructive/unhelpful to us and our relationships. The key is to identify the difference between healthy and unhealthy negative emotions.

Working in this way is called REBT, Rational Emotive Behavior therapy. There is information online about this way of working with our thoughts, emotions and behaviors. I suggest some research would be helpful to see if this resonates with you.