Oyayubihime Infinity (2004)

Blurb:
What happens when love gets in the way of fate? Sometimes it’s funny, but it’s ALWAYS bewildering. A long time 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 thumb. 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.

Source: www.anisearch.com/manga/207