<human>: Have been dating for over a year

I have moved abroad and have the opportunity to vacation with my family (Mom dad, sister and her husband) for a week in the autumn with whom I not have seen for over a year. 

My gf has not met my parents and has no ties to my family. One of her great friends is having a wedding on this weekend in another country. 

My holiday time is very limited and traveling to both destinations would be financially expensive for the duration of the stay. While discussing this issue my friend has offered to take her place if she does not want to travel on this vacation. I feel like It is a lose lose situation as If i choose to go on vacation I will upset her and if I choose to go to the wedding I will be upset that I have traveled and given up my family and holiday time to attend a wedding where I will not know anyone. My GF (2015) went vacation during the christmas holidays and as such was away during this past christmas due to lack of vacation time on her behalf. 

I'm not sure how to formulate an thoughts as anything besides going to the wedding is deemed selfish.

I hope my paragraphing is okay and /R/relationships can help me out. Throwawayofcourse.

Can you condense the text into a few key points?
<bot>: Girlfriend wants me to attend wedding, parents want me to attend vacation. Best friend to go on vacation with me in place of girlfriend