Translation:I have not come to defend my husband, but my son.
The definite article precedes a possessive adjective but it can be left out when speaking of close relatives. It is often omitted in Brazil. The possessive pronouns do not require an article except when emphasizing ownership. So I guess the question could have used 'meu marido' and 'o meu filho' and the answer would still be the same as the one Duo gives.