If you file jointly, it does not matter where the withholdings or estimated payments come from. When you file, they are counted together to determine if you have over- or under-paid your taxes.

The instructions for form 1040 say this explicitly with regard to estimated payments:

If you or your spouse paid separate estimated tax but you are now filing a joint return, add the amounts you each paid.

And implicitly with regard to withholdings (meaning it does not ask you to segregate the W2s by filer):

Add the amounts shown as federal income tax withheld on your Form(s) W-2. Enter the total on line 25a. The amount withheld should be shown in box 2 of Form W-2. Attach your Form(s) W-2 to your return.

If you file jointly, it does not matter where the withholdings or estimated payments come from. When you file, they are counted together to determine if you have over- or under-paid your taxes as a couple.

The instructions for form 1040 say this explicitly with regard to estimated payments:

If you or your spouse paid separate estimated tax but you are now filing a joint return, add the amounts you each paid.

And implicitly with regard to withholdings (meaning it does not ask you to segregate the W2s by filer):

Add the amounts shown as federal income tax withheld on your Form(s) W-2. Enter the total on line 25a. The amount withheld should be shown in box 2 of Form W-2. Attach your Form(s) W-2 to your return.