Hunter Biden's ex-wife Kathleen Buhle investigators about his business dealings

Her marriage with President Biden's son Hunter was initially beautiful

But about a decade later a drinking problem sent him to rehab, and a relapse 7 years later would begin the slow unraveling of their relationship

The memoir, written by Buhle after her divorce with Hunter Biden in 2017, details her ex-husbands struggle with addiction and infidelity, which led to their separation

"It was a painful time for our entire family," she told CBS News' Anthony Mason

Investigators are investigating the president's second son's business dealings abroad in recent years

In an interview with CBS News last year, he said he was cooperating with the federal investigation

During 2018, Hunter Biden's taxes and business dealings were investigated by the U.S. Attorney's Office in Delaware

The subpoena obtained by CBS News revealed requests for bank records dating back to 2014