Maybe, if he or she wasn’t working last year or didn’t earn very much. A qualifying partner gives you an extra personal exemption, worth $3,800. This works for same-sex couples, too.
You can claim a live-in friend as a tax dependent if he or she had a gross income of less than $3,800 last year. Your friend had to live with you all year (except for temporary absences, which could include a short spat). You also have to have paid more than half or his or her support.
If your friend wasn’t working, those should be easy conditions to meet. If you paid for his or her education expenses, you get a deduction or tax credit for that, too.
The children have to live with you full time, except for temporary absences.
”Temporary” might be weekend visits to their dad but not a co-custody arrangement that takes them away for months. You also have to pay more than half of the children’s support.