Below is a comment on a recent thread at JWR, and I wanted to share it. Obviously, every situation is different, but for many situations, I believe there is some wisdom in this advice.
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They will make your life miserable for as long as you will allow them too. Just as things are going well, and you're feeling good, they show up with a glimmer of hope that you might renew a normal relationship. Then they rip open the old wounds and you're once again treated as a leper.
They will do this over and over again until you finally say "enough." Don't worry about being the bad guy - they already think you are, and not caring about what they think is a vital part of escaping.
Tell them if they ever have doubts about the dubs to come see you, but until then you're completely off limits. Your life will be much better.