If the guilt stems from something you may have done, the realization that triggers these feelings can be used as a guide in how to react in future relationships. The guilt can be used as something that would let you monitor yourself and instead of preventing you from moving on, can be used as the motivation behind getting a clean start where you can do things differently.
Fear is another stumbling block and it is an emotion that is connected to something else ex: (trust issues, self esteem, doubt, faith, etc) and it may be helpful to note what stands behind the fear. It would be helpful to realize what things in the past relationship led to its dissolving and to see how much of that was your or your partner's doing.
In any relationship, you take the chance to expose yourself and become vulnerable and if the other person betrays or uses that against you, that is their fault not yours. You'd want to be able to separate that when you meet another person in not displacing feelings that you may have for the person from the past who had hurt or disappointed you. In order to move forward, you wold have to discard those things that no longer serve you such as fear, anger, guilt, doubt, etc. Experiences are learning lessons and you may treat them as such and not as stumbling blocks. There may be times when you'd have to forgive yourself in addition to forgiving someone else for the mistakes that were a part of the learning journey.
When the Past Is Present: Healing the Emotional Wounds that Sabotage our Relationships
To discard those feelings you would want to monitor your inner dialog (what you tell yourself, what you believe, what you ruminate on) You would also want to practice self forgiveness because you're human and every person is prone to mistakes. Making mistakes does not make you a bad or unworthy person. Other's compliment you because they see past your imperfections (everyone has those) and they rather see the real person behind. Using autosuggestion (positive mental statements) is one way to redirect your attention away from the pain and distress. www.welz.us/Autogenic.pdf
It talking with others is difficult at this phase, you may use journaling to sort your feelings and emotions and start to reflect on these in a more objective way. What transpired is in the past and you're dealing with the present now. How you think and what you do hence forth will pave the future and you can make it be different than what you want to leave behind.