I do not have any similar experiences, but generally - yes, I sometimes can feel other people's stuff at a distance. Even more so if I send distant healing.
As for techniques though - have you tried cutting (unhealthy) cords? You'd try to visualize cords connecting you to your ex, and where they are not all Light, bright and shiny, but may look grey or otherwise diseased (and as such having a higher likely-hood of conducting negative energy), you either cut them, or e.g. radiate them with healing light, inject them with some healing potion, or the like. If you want to cut and get into problems - Archangel Micheal is a good support there. Plus, if you do not already, you can obviously always pray for him, send blessings, channel healing energies for him, etc. For any negative feelings you now may have - guilt, sadness, etc - you can ask that they are taken off you, and or ground them off into the depth of Earth (for rehab and recycling).
Love and Light!