How do I reconnect with my partner? Feel like we drifted apart but I don’t know how to breakdown that wall
Based on all the uncertainty and concerns you have expressed that you have in your life that you listed your marriage seems a secondary issue and your understanding of yourself: your wants and your needs as well as who you are as a person and perhaps who you want to be as primary. This is essential to explore before then moving into the issues you describe you have in your marriage.. How can you move forward in your marriage if you don't know who you are as an individual and what you want to be? How can you know what issues are yours and what is spilling over into your marriage and causing you to be unhappy, distant and unsatisfied?
In regard to communication I reiterate first know what are your individual concerns about your own life. Be able to identify/state them out loud and as recommended, in therapy. Explore and understand what the origin of your concerns are and how they currently present. Learn more about how you can find happiness, make better choices and live a fuller more intentional life that you don't question as you feel satisfied.
Following that you can then explore the marriage, your part in it after 13 years and what you currently expect and perhaps are not getting from your partner. You can find your voice in your own therapy and then learn how to explain what you are feeling to your partner with more assertiveness and conviction. You want to be heard, believed and clear in what you are reporting about your experiences and what you would like to be different in your relationship. You will then be able to be clear to your partner and not blur your own issues that you are responsible for with those that you both have in the marriage.
You can role play in therapy to become more comfortable. You will get the support you need to better process the interactions with your partner when you are ready. You could also enter into couples therapy once you have a better sense of yourself, are more confident and the ready to take newer steps to an improved relationship if you both decide this is what is wanted.