Lamentations 1:2 (ESV)

2 She weeps bitterly in the night, with tears on her cheeks; among all her lovers she has none to comfort her; all her friends have dealt treacherously with her; they have become her enemies.

Jerusalem’s “lovers” are the nations she continuously sought for help, while neglecting to trust instead in her God. Jeremiah had warned the people of Judah that these nations (especially Egypt) would disappoint them (Jeremiah 2:36; Jeremiah 37:7). Now that Jerusalem is in great distress, none of them is there to comfort her. It has always been like that: whenever the church of God trusts in other things (such as worldly power, science, or philosophy), she is sadly disappointed.