Try messaging him on iMessage when you're suspecting he might not be at work. When he's forwarding and taking calls from an android, he won't be able to see your iMessages, and all messages he sends to you will only appear on your phone as a green bubble text message.
IMFROM9GAG t1_iu5ppxd wrote
Reply to Can a sneaky husband connect an android to his iPhone to mask calls and location? by Dapper_Astronaut3443
Try messaging him on iMessage when you're suspecting he might not be at work. When he's forwarding and taking calls from an android, he won't be able to see your iMessages, and all messages he sends to you will only appear on your phone as a green bubble text message.
Best of luck!