There's always Aerospoke wheels. They're expensive, but my
understanding is that they are extremely tough. They also have
reinforced, but heavier, wheels for tandems.

I would also make sure the chanstays and dropouts are aligned both
horizontally and vertically. If you do your best to center the wheel
between the dropouts on the horizontal plane and you're still having
problems, check to see that the wheel isn't tilted vertically.

You can do this very easily by taking a piece of string and looping it
around the rim and tire. Position the string loop so that hangs
perpendicular to the floor. Run each end of the string to the the axle
center on their respective sides and tape them down. Use a ruler or
tape measure and measure each string. If the wheel is straight the
measurements will be equal. If the wheel is tilted, the measurements
will be different.

A vertically tilted wheel means one dropout is higher than the other.
This would make the the force of your weight on your wheel directed to
one side of the rim. Ideally, your weight should be directed right
down the center of the rim. When your frame was repaired, the weldor
needed to check the horizontal and vertical alignment of the chainstays.

Another but less likely possibility is that your frame is in alignment
when unloaded but the repaired side (assuming it broke at one of the
chainstays) is weaker, so that when the frame is loaded one side
deflects more than the other. You did say a plate was welded in for
reinforcement, but it's still worth taking a look at the alignment
while the frame is loaded. Maybe you can get a friend who is around
your weight to sit on the bike while you measure.

Uneven tire wear can also be a clue to misalignment. If the tire is
worn on one side of the centerline of the wheel, or if there is a
cupped wear pattern, you have a misalignment.

Remember that a spoked wheel is designed to be strongest when the
forces on it are directed radially from the hub to the rim. While
there is some tolerance for misalignment, and short duration lateral
forces (such as in cornering) a constantly skewed bicycle wheel means
you're making the wheel carry forces in ways it wasn't designed to do.
When you do that, failure is imminent.

Oh, and it's not that politically incorrect to suggest that a female
may be better at wheelbuilding than a male. It has been shown in human
factors studies (sorry for the lack of citations, but you can find
them) that on average, females appear to be more adept than males at
work that requires attention to detail.

Jim