Subpoenaed in Divroce by subcontractor's ex's attorney

[Eric F.]

I have no idea what or why I am being subpoenaed. Basically a guy who did a bunch of work for me last year (the majority of work on 2 rehabs) is in a divorce. Twice his ex's lawyers have sent me a subpoena for what I paid him and both times I provided all the details. I have no problem with that, I get it, there is child support, etc. Now his ex's lawyer has issued me a subpoena to appear in court for their 2 day hearing.

What the hell could they possibly want from me? Why should I have to go do this? What could they need to know? This guy is NOT my employee. As a matter of fact I haven't even used him for anything in a month. This is just ridiculous. Is this common? I cannot imagine this is common practice. 

I truly cannot even figure out what they hope to accomplish. I don't even see what I can tell them. This guy put in floors, installed cabinets, and built a couple of decks. I paid him by the hour. What could I possibly have to do with the divorce? I sent canceled checks and a spreadsheet of all payments. They also have all his bank statements which I assume show the deposits. 

Has anyone been through this? What should I expect?