My partner of 12 years has dumped me because he said he does not love me but I love him with all my heart and we were engaged to be married.How can I get him back

You can't. He's made his choice. You have to accept it, and move on.

You can't force someone to love you, no matter how much you love them.

My ex is confusing me I am the one that has been with him for 12 years one minute he is telling me that he never wants to see me or speak to me again then he is ringing me for a chat he knows I want him back what should I do he is nessing with my head and my heart.

I feel for you that' s a tough situation to be in.