Seriously it's not that hard to understand why Roger's mind is not fully on tennis right now. I don't blame him, there are way more important things in life than tennis.
I'm not saying he has been losing because of this, but one thing is certain: he's not entirely focused on tennis right now.
 I just realized this post is kinda "harsh" for the moment. So congratultions Mirka and Roger. I was definitely with a smile on my face when I read the news
I don't think the marriage is something that will change him or has changed him. They've been practically married for a decade so I seriously can't see why some people see it as a big change. About you saying that his mind hasn't been in it, well really you can say that about the whole of his 08 campaign (with exceptions of course), it's not like this so called slump started in 09. I mean he is still winning against everyone but the top 4- he's reached semis or more in each tournament he has entered. His problem at the moment in my opinion is mental, and I don't believe for a second it has anything to do with being distracted with Mirka. It's not like he's suddenly fallen in love- it's a 9 year thing for God's sake. We can blame Mirkaland as much as we want during his second set lapses, but really it's about Roger taking his foot off the pedal more than anything else and suddenly crumbling under pressure.