Welcome to our forum.
I don't know that there are any quick or easy answers, or anything that will make the upcoming weekend "okay." Usually polyamory is something you have to get used to a little at a time.
You should know that polyamory and open relationships (or anything involving at least three people) come in many shapes and sizes. There is a book you might consider reading: "Opening Up
," by Tristan Taormino.
On this site, you might want to check out the Life stories and blogs board
. It is all about ordinary people and the way poly works (or sometimes doesn't work) in their lives. The site also has search and tag search functions.
I hope you and your wife will take things slow and work things out in your own marriage. It sounds like there is a lot of fix-it work to do.
We'll help on this site however we can.