My separation was more alienation due to a contentious divorce rather than chosen estrangement. I was separated from my teen sons for almost two years. I tried everything I could think of, dripping love and memories whenever I could yet they were met with rage, vulgar names, and threats of legal action. After the divorce my former husband decided to sell the family home he fought so badly for, got married quickly, and dumped our boys. Reunification was extremely difficult because they'd been brainwashed to hate me.
It's taken almost two years to build trust back, after lots of "I can't do this." My youngest is now estranged from his dad, his dad's choice. My eldest is an adult and lives with a friend, he was alienated longer and holds me in distrust and resentment still…although he returns my texts and sees me occasionally…living in a neutral home has been beneficial but we have a ways to go.
Usually you hear about father's being alienated...it happens to moms, too!