Stay - a TW fanfic

When Anne fell in love with Siva, she would have never expected to end up the way she did. What to do when you fall in love with someone else and that person loves you back although you're both in happy relationships? Are they going to stay with their partners, hoping they will be able to forgive them or are they fighting for their own love?
Teela first met Nathan at a party, they were both immediately attracted to each other but is this attraction enough to have more than only a one night stand? What to do when something happens no one of you expected to happen and brings drastic consequences along? Will it make them be closer than before or only tear them further apart?