How do I tell my partner that I no longer love him?

I've been with my partner for 12 years and we have one daughter together, who's eight. I've come to the conclusion it would be best if we split up, but I have no idea how to go about telling him.

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We've been having problems for a couple of years at least. And I feel he gave up on the relationship - he never made any effort, so I think I gradually detached myself from him. I did tell him how I was feeling a while ago, but he said hed try harder and he has, but it hasn't changed my mind, the damage has already been done.

It's so hard, though, to break up my family. Our daughter means everything to us and to see her hurt would break my heart. Every time I've tried to tell my partner what I think we should do, the words won't come out. And I feel extra bad because I know he doesn't want to lose me and he is trying.