How long before the novelty wears off?

I'm with a guy who just got out of a two year relationship. Everyone says he will leave as soon as the novelty wears off. How long does that usually take in a rebound situation? We have been friends for years and he says he is comfortable with me but the sex is really good. It's only been two weeks. He still talks to his ex and it's been less than a month. How long before the novelty wears off?
+1 y
he has been texting his ex and trying to be friends with her and kind of talking to her like they did when they dated. I went through his phone ha ha but he says he is over her which seems a bit strange since a few days before he broke up with her he was telling her how much he needed and loved her but people can change their minds. I just don't want to get hurt and he seems to realllly like me but I am worried he has just misplaced his feelings.
How long before the novelty wears off?
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