Oyayubihime Infinity

Oyayubihime Infinity summary:

Long ago, a group of friends banded together—and now the whole gang has been reincarnated in the present day. Each has a reminder of the past: a butterfly-shaped birthmark on their thumbs. When the marks touch, they catch a glimpse of their shared past, though what they see doesn't always match. Tsubame insists that he and Kanoko are fated to be together. By the time Kanoko finds out it's not true, it's too late: she's already fallen for him. The "butterfly" friends must reconcile their ties to the past with their present desire for fun and romance!