I think Sasuke's emotional spectrum was consumed by hatred over his brother at such a young age and in such a traumatic manner that his normal mentality when interacting with people in the areas of trust and friendship that it not only made it difficult to make friends for sasuke but to trust anyone or accept love from anyone as legitimate since the person that he loved most and that loved him most, his brother Itachi, had betrayed him... Basically I think the trauma of the Uchiha massacre and the emotional and psychological impact to Sasuke at such a young age, especially during the emotional development stage of life in his teen and preteen years, has made it nearly if not impossible to comprehend the idea of love with another person... the only way he could is if he joined back with the leaf and spent time with his friends as a form of passive living mental rehabilitation, like when he joined squad seven and became friends with Naruto and Sakura diverted his emotional spectrum away from hatred of Itachi and towards loving his friends... But I think that since his leaving the village it has gotten worse and especially after Itachi's death and his new found hatred for the leaf and chaotic and murderous life style have only worsened his disposition with humanity in general...
Simply:
I Don't Think Sasuke Can Love.