The Stromata, Book III is available in Latin in a number of places, including New Advent. There is an english version at Early Christian Writings, though not authoritative.
earlychristianwritings.com/text/clement-stromata-book3-english.html
Book III does not mention Peter witnessing his wife’s martyrdom in Rome. However, it does state that Peter and Philip had children. Those still could have been from before Peter’s discipleship, though. The relevant section is here (52 and 53.)
With regard to Paul’s “consort,” it appears that its use by Clement was not in the manner we would use it today because he says the apostles took their “wives” not “as women with whom they had marriage relations, but as sisters, that they might be their fellow-ministers in dealing with housewives.”
This is the same passage from Corinthians where Paul is not stating he actually has a “consort,” but merely answering critics of those who do have “sister-wives” with them. Basically, Paul is saying he could exercise a right like the other apostles but chooses not to. I think Clement could be misreading since Paul doesn’t actually say he has a “consort,” but merely that he could travel with one in the same sense that the other apostles do. I think we would be reading into the text our meaning of “consort” if we take such liberties with it.
This doesn’t really settle anything because the translation is not an authoritative one nor does it attempt to reconcile the use of the English word “wives” in the translation with the fact that Clement only mentions Peter and Philip out of all the apostles as having children. Surely, in Judaism at the time being “married” would have brought about children - many children. Why only mention the two apostles as having children when normal conjugal marriage would have undoubtedly resulted in a number of children for each apostle had they actually been married at the time.