By Alexia FernandezOriginal Source: people.comMarlee Matlin says she has a lot to be thankful for as she celebrates 31 years of sobriety.The Oscar-winning actress, 52, shared a photo on Twitter Wednesday smiling as she proudly held up her 31 years clean chip commemorating the occasion.“Ending my day, so grateful that today, I am celebrating exactly 31 years of sobriety. #grateful#thankful#sober,” the former Dancing with the Stars contestant tweeted.Matlin previously battled drug and alcohol abuse and was in rehab when she found out about her Oscar nod for 1986’s Children of a Lesser God. The star credits Betty Ford for helping her...click here to continue reading