If you have proof that she was unfaithful, then there should be no alamony to be paid by you for support.
Thats plain BS if she thinks she can get support from you!
Since the detective knows that she is lying then your on the right track.
Did she have any bruises on her? If so did they take pictures to detail it?
if you did put your hands on her even to protect yourself you'll get arrested in todays world because domestic abuse is something that the justice system is being really careful about because it usually leads to someone being murdered.
Just keep your head up!

I know family and friends will be there for you and thats all you need.
I'm sorry about your nephew may he res in peace.