If you are filing a joint return AND using the online program then that will be difficult. I guess you could compute the return with him filing separately and then switch to jointly and then keep adding one child at a time to see the differences in the refund with each adjustment ... not sure if it is worth the effort.
".......with my husband"
Sort of....but how did you file? Did you file married filing separately or a joint return? If you filed MFS you lose a lot of child-related credits like earned income credit, childcare credit and education credit. If you file a joint return you are eligible for all of the child-related credits and they will be in your one joint refund.
Look at your 2019 Form 1040 to see the child-related credits you received
Child Tax Credit line 13a
Credit for Other Dependents line 13a
Earned Income Credit line 18a
Additional Child Tax Credit line 18b
Child and Dependent Care Credit line 18d