I read this poem several times; I found it so beautiful. Such a sad story. In the first part of the poem, I love how you portrayed the happiness this person brought you, while having the sad undertones as well. You depicted your love, happiness, and true sadness absolutely wonderfully. The most powerful part of the poem, in my opinion, was the last portion:
eventually at the end of time
Maybe we will end together as one
maybe not this life of mine
Maybe another life, under this sun
To me, this was the most heartbreaking part. You are still holding on to some hope, regardless of how much pain she has caused you. It is so touching.