Clarke gets really affectionate when she's tired and it isn't in Bellamy's nature to just walk away.

Children of Men/28 Days Later AU, Bellarke. It's been sixteen years since the last child was born. When they thought they'd found the answer to species-wide infertility, the side effects proved extremely lethal. The last of humanity now lives in a walled-off city known as the Ark. Clarke is the daughter of the head doctor, and Bellamy is a prisoner about to be hung.

Clarke has been extremely stressed recently. She has to act as the camp's doctor and lead alongside the annoyingly attractive Bellamy Blake who rarely agrees with her on anything. After what happened with Finn, Clarke is determined not to let attraction blind her again. But when things start to change between her and Bellamy, will she be able to deny her feelings forever? Bellarke

The 100 escape the campground and make their way to the Atlantic Ocean before the grounders arrive. As living on earth seems to get easier day by day, the group have more time to worry about the "simpler" things in life...like relationships... or at least thats what his sister says... Bellamy on the other hand would prefer going head to head with a 200 pound grounder.*Bellarke*