The sword of cruelty, from now on, will walk every moment with her; with our own heads, we have tied the shroud.

This couplet beautifully captures the depth of emotional pain and resignation. The speaker acknowledges that the beloved's cruelty (the 'sword of oppression') is a constant presence in his life. However, his response is even more dramatic: he has tied the shroud to his own head. This act signifies that the pain has become so unbearable that he has emotionally accepted death, finding a strange kind of peace in that ultimate surrender.