How would Reformed Christians deal with homosexual marriage of individuals prior to their conversion to Christianity?

I've been pondering this for several weeks and I believe that the reformed church (really, the church in general) is woefully unprepared to answer the following question: *How would the church deal with a gay couple that were not Christians when married, that then become Christians?* Specifically when we have passages like 1 Corinthians 7:17 (NIV) > 17 Nevertheless, each person should live as a believer in whatever situation the Lord has assigned to them, just as God has called them. This is the rule I lay down in all the churches. I'm looking for relevant biblical quotations, relevant quotes from reformed scholars past and present, and any statements by reformed churches or denominations that have come out in recent years. I'm also interested in how circumstances and views change when 1 partner becomes a Christian, when there are children involved, and when both partners become Christians. As gay marriage becomes more prominent, legal and prolific in our society, questions like this are going to be more and more relevant and the Church must be prepared to deal with an answer these queries. I'm specifically interested in reformed sources here as they are most relevant to me, but I would be open to other sources that take a similar view of homosexuality.