I believe it, for the most part. Not that it was the ONLY reason he left - but I think it most likely played a pretty big part in it. And even Stevie didn't say it was the only reason - just that it was one of the reasons
Stevie has a very dramatic way of wording things, for sure, but I think the essence of it probably rings pretty true - he didn't want to be around her anymore, really, and I'm sure that was influenced by her behavior/state of being at the time.
I doubt if that is just some theory that randomly came into Stevie's mind in that moment. I'm sure they've discussed his departure in the 20+ years that have transpired since. And as crazy as Stevie is, I don't think she'd say something like that if it wasn't something that had come up before. In the article, the interviewer said she turned to Lindsey half-way through her statement, as if to confirm with him that what she was saying was true,
Again, the sensational way in which she described it - "his beloved ex-girlfriend was going to live" so he could join FM again

- probably (maybe definitely :laugh) a little over the top. But in essence, I don't see that it's all that bizarre of a "theory."
And while I enjoyed Mick's book, I don't take any of the specific details as cold hard facts. Lindsey isn't British.
