I used to write wills for a living and I'm happy to back up one of AB's resident solicitors, Danny, on this one.
Unless the wills were drawn up 'in contemplation of marriage', they were automatically revoked by your marriage.
Even if you weren't expecting a child, I'd still question the wisdom of assuming that, when one of you dies, everything automatically transfers to the surviving partner. When faced with a couple who asked me to prepare wills transferring everything to the surviving partner, my first question was always "OK, so what happens if you both die in the same car crash?".
Go to a solicitor and outline your situation and requirements. If he doesn't start asking lots of questions such as "Have you considered the situation where . . ?" or "What if x, y and z happened . . .?", walk out of his office and find a solicitor who actually knows how to do his job.
Chris