How do i tell my husband i dont want to be with him anymore without to much heartache?

There's no way to avoid the heartache but the best thing you can do is tell him honestly, soon, and without being ambiguous. Don't drag it on forever, don't cover up how you really feel so you can spare his feelings, and don't give him hope that you will change your mind or that there might be a chance (if there isn't) because that causes serious heartache that lasts a long time with the twinge of hope.