I have been married nine years recently found out my husband was previously married in 1993 and never received a divorce

You need to get an attorney in the county in which the case is filed. The divorce papers may contain important evidence sufficient to defeat the...

Will time-sharing/decision making authority remain exactly same as in petition for dissolution of marriage if case is default?

That depends on what evidence is presented to the Court when it considers the default.

I'm an expatriate seeking to file for a divorce. My wife is living in Manila, Philippines and I'm working in South Korea.

If you meet the requirements in Korea you can file there. Otherwise you will have to return to your home state (or another) and meet the residency...

How do I enforce the terms of a divorce decree?

File in Family Court.

Is determining if my great-grandparents' marriages were legally valid sufficient grounds to get very old divorce records?

You can check index number files but you may find limitations on looking at the divorce/paper files in the NYC archives.

Yes. It's necessary for any divorce filing.

Do I need a legal aid?

This isn't a divorce question - but a judgment is good for 20 years.

My wife moved out almost eleven years ago. For an ex boyfriend. If I were to divorce her, could she collect alimony from me?

Probably not. But she might very well get a portion of your pension.

I am legally separated. What should I do to finalize the divorce?

You can convert the agreement to a divorce by filing the appropriate case and the relevant paperwork, and then following the appropriate procedures.

I'm in mid-divorce with my spouse. Since I have her SSN, can I lawfully run her credit report in the absence of a court order?

Why not? But - why?