I often feel the same way, the want/need for being unalived is so strong and yet so is the hope that one day things will get better. The way I get through it is by trying to remember that having this thought of "One day, good things may happen or be better than they are now" is a sign that you have a strong will to live and are resilient. Sometimes, even if we don't want to be resilient or perseverant, we just are, and in situations where CTB would be ideal well... It makes it very difficult to take that step.
On the other hand, there's the argument that good things won't happen or things won't get better since the relative part of you won't be around anymore. For example, since you can't experience happiness or good times when unalive, then these things won't happen regardless since you need to be around for it to happen. You can't win the lottery after you CTB basically. But I think where this theory ends is when you start to think about what would actually make you happy or be good if it happened and you experienced it? And often times the things that would make us happy or feel great are things that don't always necessarily happen directly to us, but to those around us that we are attached to and by affiliation, you share their joy or their happiness. Such as your family gets a new puppy, your CTB may not stop this from happening and it may still happen without you, meaning you won't be able to experience the joy of raising the dog and them become apart of your family.
And then finally, there's always the possibility things might get worse. Trust me when I say, you might think things could not be worse than they are, but you'd be surprised how far you can fall. The pit actually is endless and it can get increasingly worse. I'm not sure where the point of the worst is as it is so far down that I am sure that anyone who really reached the bottom of that hole is no longer with us. But the important thing to take away from this negative statement is that the further down the hole you are when you climb out of it, the stronger you are. The fact you have hope/thoughts about a better future already shows you have strength. So just try to remember, the further you fall, the stronger you will be. You can be unbreakable!