How to effectively communicate my emotions in a relationship?

Breakups are tough for many reasons.  Some breakups bring regret, others make us question what we want in our lives, most bring insecurities to the surface.  There is healing that has to occur after any breakup, but it is an opportunity to look at ourselves at a deeper level and make changes that can make our next relationship healthier.  As far as the betterment of yourself, that is so dependent on more details than what is provided here.  I can say some generalities. 

You need to look at your attachment style and how that has affected past and the most recent relationship.  Secure attachments make for the most stable relationships, but many people are not able to securely attach for reasons that go into their childhood. 

Anxious attachment is an attachment style that forms as a result of not being freely given love and acceptance in childhood.  People with anxious attachment cling onto relationships, even unhealthy relationships.  They feel emeshed with the other person and often put their needs to the side to keep the other person.  Anxious attachment is characterized by very strong emotions and driven by a deep desire for receiving love from the other person.  There is also sometimes great fear that they will lose the person and subsequently lose the love they feel.  It can lead to smothering in relationships and a great difficulty in getting out of toxic relationships or any relationship because of the strong attachment.  People with anxious attachment have a hard time trusting others and often feel incomplete when the other person is not around or responding to their needs.  They feel a need for strong reassurance and frequent displays of love and affection.  In unhealthy relationships, the anxious person will often double down if the person pulls away.  As stated earlier, breakups can feel devastating in this attachment style. 

Dismissive avoidant attachment is quite the opposite and also a result from unhealthy childhood attachment when they felt their needs were neglected.  Dismissive avoidant attachment people usually have a hard time identifying their emotions and connecting with others emotionally.  Dismissive avoidants often are noted for their independence and resiliency, but the downside is that they really struggle to connect to others and often are also called cold or distant. 

Fearful avoidant attachment style is the most complex attachment style as the person feels anxiously attached at times and avoidant at times.  They often pull the person in just to push them away.  They often become very anxiously attached if they feel rejected or feel the other person is pulling away and may reject the person if they feel they are too close.  The underlying fear in this attachment style is that the person will leave them and they may reject the person because they subconsciously believe the person will ultimately reject them. 

These insecure attachment styles are often based in traumatic experiences, most common from childhood.  It may be that none of this applies to you and that you securely attach.  That would likely only be the case if you felt unconditional love and acceptance and that your needs were met in your childhood.  But even if that is the case, there is useful knowledge to be learned on why others you may date act in certain ways.  If you do identify that you have an insecure attachment style,  it is an important opportunity to process the underlying issues that caused your attachment style and learn more about why you act and feel certain ways in relationships.  If you do have an insecure attachment style, it is imperative that you work on the underlying issues or your relationship theme will likely continue. 

Breakups also give us an opportunity to look at who we are and what we want and need from a partner.  There is also the opportunity to look at ways we do not communicate well and work on ways to better communicate in the future.  There are many other issues we often need to address before we can be our healthiest selves, from anxiety and depression, to negative self image and self talk.  Most people struggle with insecurities and a breakup can give us an opportunity to identify and work on the reasons for our insecurities. 

Fortunately, all of these issues can be addressed in sustained therapy with a competent therapist.  We should also look at patterns in our lives and our relationships and work toward fully accepting, loving, and many times forgiving ourselves.  I have always thought that the greatest sign that we can be healthy in a relationship is when we no longer "need" a relationship to feel OK about ourselves.  We often seek from others what we can only get from ourselves.  If I am not happy or at peace with myself, a relationship will never fix that.  It is only a bandaid that when the newness of the relationship wears off or problems arise in the relationship or even in life, the same insecurities and negative self view will appear.  Better living is possible only when we are at peace with ourselves.  No relationship or other life circumstance can give us the ability to truly enjoy life.  When we reach this place, we are able to be enriched by a relationship, not continually seeking for someone else to make us whole or complete.  I know this response is very broad, but it has to be because the question is broad.  I can say that therapy might be the best investment you will ever make in your life and in your future relationships.  Many times we take great measures to help ourselves in physical or financial ways, but take little thought for improving our mental health.  I hope you continue on this journey and I wish you the best in your endeavors.