Dating ex husbands aunts grandson?

-My bfs grandma is my exhusbands aunt. We are all in our late 20s and my ex is adopted so no blood relation but what is their relation?Your ex-husband's parent is sibling to your boyfriend's grandmother. Your boyfriend's parent and your ex-husband are first cousins. Your boyfriend is your ex-husband's first cousin, once removed.
By law they are affiliated, but not that close.