My husband won't talk to me about certain issues?

My stepson has a prescription drug addiction (progressed to crushing the pills and injecting them). He's sitting in jail in WV right now, and my husband is tight-lipped with me about the whole situation- but he just spent an hour on the phone with his ex-wife (stepson's birth mother, who abandoned him when he was 2). Why does he feel the need to talk to her but not me? I have been there for him more than she ever was.