Does anyone know if I can call his attorney to get the status of the D papers? First of all, is it allowed and second, is it a bad idea?
Yes, it's allowed.
Once you have an attorney, they will be doing this on a regular basis. For now, you represent yourself. If you are unsure of whether a Complaint for Divorce has been filed, his attorney's office is the place to ask. If it has been filed, you should have been served, unless it was in the last few days.
If it has not been filed, then it was just a draft, and since it is six months old, you might as well not worry about it. Go ahead and get your own attorney and file yourself. You are the injured party here and you are the one with the most to lose by delaying. You can't wait for him--he may let things go until he has sucked everything he can out of the marriage (and the barn).
As for whether you SHOULD contact his L, maybe not. If you call, they may inform their client, and he will be forewarned that you are perhaps planning to file. Since you need an attorney anyway, get one first and have him contact the other attorney if he thinks it is wise, vs filing first.