i hope you do not find this heartless
but fakhert, the other way around, the Rambam states that to attribute ones misfortune or unhappiness to others is a way of cruelty. there is a Passuk (or perhaps a
Chazal, i forget the source) that no good thing, or no damage comes from Hashems creations, without the permission of the Boreh, Yisborach.
it is not our way to view ourselves as victims of others, to be concerned with others ways (unless we are able to properly correct them).
you need not concern yourself with the insensitivities of others, you must not nurse grudges. this is not permitted, and it will not lead to an improvement in your situation.
you need be concerned only with yourself. how do you treat others? how sensitive are you to others needs? how can you improve yourself? do you recognize that your troubles come only from Hashem? you must realize this and increase the intensity of your Teffilos. Daven for others who are single and do not wish to be. Daven with great Kavanah for them.
Rabbi Ephraim Wachsman brings a different interpretation to the Amirah that” if you Daven for others and you need it, you will be answered first.”
“if you need it”, if you NEED that the other person be answered, if you feel for them deep in your heart, then YOU will be answered.