Head of Household Not Clear

I live with my boyfriend and I have one child that I claim (not his child). It is really hard to say who pays more as he pays for the mortgage and I pay for food, utilities, etc... He files his taxes as "single", so can I file as head of household?

I am not really fond of thse situations.

Tax wise, it would be best if you and your boyfriend were married and filing jointly.
Also, there are other legal advantages to being married.

Is there any child support paid by the child's father? That needs to be asked just to muddy the water a bit.

The question you need to say yes to is, Did you pay more than half of the houshold costs of keeping up your home lived in for more than half of the year by your child?
Then you can file HH.