<human>: Condense the text into a few key points

I broke up with my bf like 2 months ago. It was a total clean break – completely no contact and I've not seen or heard from him since. We were together for nearly 2 years so the break up was kind of rough and what made it worse was that I was close with his family, especially his sister. 

I hadn't spoke to her since the break up – I figured maybe she didn't want to get involved and she is about to get married so is real busy. Today I got a message from her, apologizing for not being in contact but letting me know the final details of the wedding (in 2 weeks time!). She told me she has a hotel room booked for me and Sam (my ex), wanted to know when our flight landed and other final details of how she wants me to be involved in the wedding.   

From the whole tone of the message I realized Sam hadn't told any of his family that we had broken up. I feel in a really awkward position because if I tell her we've broken up she's going to have to change her wedding plans at short notice. I guess I still could go but that's going to be awkward if Sam's going to be there. I could talk to him first but that probably wouldn't go that well because we had a pretty rough break up. Any advice on how to not upset a bride who is probably already stressed as hell?
<bot>: My ex-bf didn't tell his family we broke up and now his sister has all these plans for me to be involved in her wedding.