Honestly, I don't understand your reasoning. Atheists have no reason to believe in deities, but that does not mean that they do not enjoy life. To the contrary, from the perspective of most atheists this life is the only existence one has, so they are not prone to give it away lightly. Death is the most unattractive part of life that we know is coming, why would anyone look forward to it?
If you truly think about it for a moment, a person that believes in an afterlife in which they will be with their favorite deity should find death much more attractive than life, because they are promised a better existence. Existence doesn't end for them upon death. Those that don't believe in an afterlife are much less likely to find death attractive, as it means the end of their existence, period.
I know most theists have a hard time understanding this, but if you can find beauty in the world as it is, and can enjoy being good and living well and honorably WITHOUT a reward or punishment for doing so, then life is well worth living. Even if things are going horribly wrong in your life, you realize that it's the only life you have, so you might as well enjoy it and bring some joy to others. There is no time of reckoning, reconcilliation, atonement, judgement and forgiveness after death for those that don't believe in an afterlife, so they are much more likely to take care of all of those things while they are living, so that they can enjoy the time that they do have in this life. Life is worth living, and that is not dependent on the existence of deities.
Basically, it boils down to a difference in perspective: theists may claim that life is not worth living without their favorite deities, while atheist don't have a reason to believe in deities, and therefore no reason to be upset that they don't believe in them. In all honesty, thinking that going through life isn't worth it, or that life has no purpose without an afterlife, is a little troubling. If the only reason to live is to ensure a good place when you die, if the only purpose to life is to serve something that can't be seen until you die, if life just isn't worth living, then perhaps you should seek professional mental therapy. The promise of an afterlife does NOT give you reason to cling to this life, it gives you reason to forsake it. Atheists have very little reason to forsake this life, and every reason in the world to cling to it.
p.s. as for suicide being honorable, only in certain cultures under certain circumstances. Again, an atheists feels no need and definitely no rush to end this life, as for most it is all they have.
Here's a link that may help you to better understand. Have a great day!