Simon Lewis, of Trowbridge, died after the Daihatsu Sirion he was driving collided with a blue Peugeot 307 on Lamby Way at 17:30 GMT on Thursday.
In a family tribute released by police on Friday, Mr Lewis was described as a "wonderful father and husband".
The other driver, a 29-year-old man, is in hospital with non life-threatening head injuries.
A woman, 32, and a three-year-old child travelling in the Daihatsu were discharged after hospital treatment.
The family tribute said: "Simon was married to his wife Amanda of seven years and they had a daughter named Summer. He was a very popular man who lived for his family.
"He was a wonderful father and husband who was looking forward to the birth of his son.
"He will be greatly missed by his family and friends and is someone who will never be replaced."
Officers have appealed for any witnesses to come forward and to contact police on the 101 non-emergency number.
A 33-year-old man from Cardiff killed after a head-on crash on New Year's Eve has been named.