Have to put my cat to sleep.

I feel it's for the best but it's still like a spear in the heart. I have another cat but one animal can never replace another. He's got multiple health issues that can possible be resolved but only for a very short time. He's 15 years old and not wanting to see him suffer through more flare ups that are sure to happen I've decided to let him go. I will miss him a lot though.