Meanwhile, Peter's entire motivation for doing what he does is, "With great power comes great responsibility." So if you consider superheroics while having a child to be irresponsible, that would be a little contradictory.
For what it's worth, Renew Your Vows is actually making me want to see a married Peter/MJ as parents become the established canon. If Miles is taking over as our one young Spider-Man, then I don't see a problem with them writing an adult Peter that's a little more tied down. There's enough variety between the characters to collectively hit all the right notes.
But if MJ is going to show up somewhere unexpected post-Secret Wars, I assume that can only mean it'll be outside of Amazing Spider-Man? So I shouldn't expect to see them tying the knot anytime soon. If ever.