US qualifying child question

Hi! Quick question – I have a child from a previous marriage. Should my husband add them as a qualifying child? I will only have about 2-3 weeks worth on my taxes to file next month, he’s worked all year. We’re legally married & have our own child together, he’ll claim that one on his tax forms. Should he add his stepchild as well? And I just won’t claim either one on mine? Or do I have to claim my bio since they would be on my tax forms from when I filled them out last year? I’m so confused, please help