Losing a bond is always a drag. Its awful for both parties involved, I understand that. What I do not understand are people who forcibly want to insert themselves into your life or who will not let a bond dissipate and seek to inspire guilt in the ones that make it so.
Being someones former partner does not give you an entitlement to their time. They do not owe you a friendship; they do not owe you anything. If they need to end a bond because it has become unhealthy for them, yeah it sucks, and yeah you should feel what you need to feel, but ultimately that is their choice.