I'm sorry it got to this between you, and that you gave in to her wishes of marrying you, she must have been exhausting. She doesnt seem to understand that even if you dont marry her, it doesnt mean you dont love her fully and want to make her happy. It seems to me she interpreted it as you not being ready and being scared, so she felt she couldn't fully reach to your heart, or that you are committed and dedicated while that might not have been the case.
I'm thinking she is not able to believe you're not actually flirting and are oblivious to such things being on the spectrum, what adds up to it must have been that you have not returned the same observations shes been needing to feel loved, and she felt neglected and refused after displaying distress and needing it, even if it was negatively, and betrayed because you did it to others. She needs to learn to express her needs healthily, explain herself and have an open mind towards you, your autism and have patience. She seems to not be able or know how to deal too well with jealousy. There must be communication issues and trust issues which failed to be resolved. Over time her suspicion and hatred only grew, that's unfortunate she couldn't see you for the honest man you are.
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My Pepe Le Skunk. I have so much faith in our love for one another. Thanks for being an amazing partner. 
x

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