Check your own bank account for deposits of the stimulus checks, and check your online account with the IRS to see what the IRS shows they sent to you.
Try checking your online account with the IRS (and if you filed a joint return—check for BOTH of you)
https://www.irs.gov/payments/your-online-account
If you need to trace a payment that the IRS says has been issued to you, mail or fax a completed IRS Form 3911, Taxpayer Statement Regarding Refund.