I believe that same-sex couples may not only be permitted but may indeed have a religious obligation to marry the one they love & are fully and exclusively committed to. It's true that according to one Talmudic approach, the purpose of marriage is to procreate together. But another Talmudic approach explains that the purpose of marriage is to liberate one another from the depths of existential loneliness. Indeed, this is a deep religious insight of the rabbis that marriage is just not just about family but also deeply existential. In Jewish thought, love is not a strange emotion to be conquered. Rather, love is a spiritual value to be cherished & celebrated wherever it is found.
"Rav Nachman said in the name of Shmuel that even though a man has many children, he may not remain without a wife, as it says: ‘It is not good that man be alone.’ But others say that if he does have children then he may abstain from procreation and he may even abstain from taking a wife altogether," (Yevamot 61b).
תלמוד בבלי מסכת יבמות דף סא עמוד ב
מסייעא ליה לרב נחמן אמר שמואל, דאמר: אע"פ שיש לו לאדם כמה בנים - אסור לעמוד בלא אשה, שנאמר: +בראשית ב'+ לא טוב היות האדם לבדו. ואיכא דאמרי: הא יש לו בנים - בטיל מפריה ורביה ובטיל נמי מאשה