I am 45 years and having an affair. What do I do to see that I get the full alimony and my divorce proceedings go on smoothly.

Divorce proceedings wise, if you have been married for at least 3 years, if the fact of adultery can be proven, then divorce can be granted. As for alimony, it will be up to the Court to divide assets. http://singaporedivorcelawyer.com.sg/adultery-faqs/