Your lover will have a hard time understanding you or your feelings. You didn't trust this person in another life, either because they out-and-out betrayed you or because circumstances beyond either of your control led to your heartbreak; either way, in this life you'll feel a subtle, even unconscious need to self-protect. You may find yourself feeling or perceiving things about them that you won't call to their attention, even though bringing your fears or suspicions out into the light would be a much better, more direct way to deal with them.
But your instinct will be to maintain that sense of secrecy, which will ultimately lead to a mutual feeling of distrust. Your partner may try to push or even bully you into having it out with them, which will only compound the problem; or they may simply live with the feeling of unease that will permeate your connection. But a much better way to deal with this problem will have to originate with you. Bringing your fears to light will be the only way to eradicate them once and for all, and ensure that you don't carry them on to the next life. Otherwise, your secrecy and emotional withdrawal will end up causing your partner to pull away in a very real and tangible way. If the relationship is important to you, you'll have to push yourself to open up in ways that will feel foreign, even scary, to you.