What is the way to repent and deal with a situation that combines intense love for a friend, lying to him to prevent him from distancing himself due to misjudgment of him, and fear of telling him the truth to avoid hurting him?

Love that reaches the level of attachment and infatuation is reproachable and may even lead to shirk (polytheism). Lying is forbidden, though it is permissible for an overriding benefit. However, lying is not permissible to maintain a sinful relationship. One must repent from lying and sever the sinful relationship. There is no need to inform him of the lie; it is sufficient to pray for his well-being.