My husbands ex wife taking my husband to court ...

Mandi • Married in March ... Just found out pregnant in October
Long story short we got a letter explaining that my husbands needs to send his child support checks to a new location ... Inside was all custody info and such on there ... My husband said it was private between him and his ex wife that he didn't want me to see it ... Eventually I saw it and it says he gave up SOLE custody of his son ... He never told me this ... How should I handle this ... Advise plz ... Ty !