Leaving you did kill me, in a lot of ways. Spent ages trying to find a way to fix it. Granted, wasn't technically in this body at the time, but I was there, so to speak. Timey-wimey. Anyway, my point is it was terrible, but I knew it was final. I didn't know what to do. Then events caught me up, and you came back. It was different, and you had to become so much stronger to make it.
You had been hardened, and it was my fault. Then the split happened, and my different Rose and I had to carve out our own life. It's not the way I think either of us would have picked, but the end worked out, didn't it?
We're both living our lives for each other. In our own ways, don't we get forever?