On the other hand, there's Roman tomb that has a fairly lengthy inscription about those buried in it and two of them were a Roman woman and a former slave who she'd freed and married, so things were evidently a bit more flexible in that area then you'd think.
IMO, that sounds rather exceptional. It would almost be akin to saying that since Queen Victoria was the wealthiest individual with the largest amount of land owned in Great Britain, all British married women in the Victorian Era could become wealthy landowners.
However I do believe that there were cases in which the offspring of Roman citizens' wives and their male slaves were passed off as the male Roman citizens' own progeny that never made the written 'radar'. While a good deal of that may have happened due to simple deceptions on the actual parents' parts, in some cases, this may have happened with the consent or even encouragement of the male Roman citizens themselves who may have been motivated to use their wives' offspring to disguise their own sterility and to pass the properties to them rather than detested actual family junior members.