None of the considerations about what DC does answer why someone would think it’s okay for other Marvel heroes to marry and have children, but not Marvel's biggest character. As Spider-Man is Marvel’s flagship character, that should restrict the company somewhat in developments involving the character, given how important he is to the shared Marvel Universe. But let's see how writers of the other superhero franchises have dealt with superhero families.
Black Panther and Storm
Black Panther and Storm’s marriage was a marriage within the Marvel Universe which occurred under Quesada’s watch, so many suggested that it was hypocritical for him to support it while trying to undo the Spider‑Man marriage. However, the wedding of Black Panther and Storm affected less books in a less significant manner than the wedding of Peter Parker and Mary Jane did, as Storm is part of an ensemble and Black Panther has one solo title, meaning that their private lives just aren’t as important as Spider-Man’s.
Black Panther's first appearances in Fantastic Four, Captain America and The Avengers made no notice of his marital status, and Storm's romances were also an insignificant part of the X‑Men for the first few Essential X‑men volumes. Nightcrawler had a crush on her in the early issues, and Doctor Doom flirted with her in her 50th issue of the X‑Men, and I think that was it. Peter Parker got shot down by a girl on the second page of Amazing Fantasy #15 so his bad luck with women was established in his first appearance and has been a major part of the character’s appeal since then.
Another recent Marvel marriage (this one included a kid) was the one between Luke Cage and Jessica Jones. From my understanding, Luke Cage was married or engaged in his first appearances and/or before he went to prison, so he has always been established as the marrying type. He also hasn’t had a solo series for a while. Meanwhile, Bendis decided that Jessica Jones’s solo adventures were over after writing 28 issues of the character in Alias. The Spider‑Man writers don’t have that luxury.
Bendis was able to have Jessica Jones and Luke Cage become a part of the ensemble in The Pulse and New Avengers which is why he was able to make their private life more stable. Neither has a monthly book (or three) to support for an indefinite period of time, and because of their edgier origins (Jessica Jones was created as the star of a Mature Readers title, and Luke Cage was always meant to have street cred) Bendis and other writers are free to explore complications you just can’t do with Spider‑Man, such as infidelity. If Luke Cage and Jessica Jones were to get a divorce, there’s a very slim chance of it being a major story on CNN. Bendis is also able to play around with the possibility that their marriage will come to an abrupt end, as he did in New Avengers #38. And it's possible that they won't even be on the Avengers after he's off the book.
The Fantastic Four
Many have compared Peter and Mary Jane to the first couple in the Marvel Universe: Reed and Sue Richards. There are several reasons why Mister Fantastic and the Invisible Woman can be married with children, and Peter Parker shouldn't. Reed and Sue have been together since the first issue of The Fantastic Four, and the writer and artist of that issue created the stories in which they got engaged, got married, found out that they were expecting a child and had a son. This all occurred long before Stan Lee realized that the Marvel books would be around for a while, and decided that the illusion of change was more important than actual change.
Franklin Richards hasn't really aged much since the beginning of Byrne's run, and with the exception of the addition of Valeria Richards and the formation of the Future Foundation, the status quo of the series has remained ultimately consistent. Johnny Storm died, but he came back. He married Ben Grimm's ex-girlfriend, but she was really a Skrull in disguise, so he was back to his old self soon enough.