I'm not watching you shoot so I can't tell you what it is that's happening that is making this occur, that graphic posted is great for right handed shooters and is easy to flip when you practice support hand or for left handers. Some of the tricks listed also help tell you the same thing.
Stop going to the range with your spouse for a bit. I know it sounds mean but because of how that dynamic works for 99% of people out there, at some point it ends up adding pressure to preform rather than a learning environment where mistakes are ok. I give the same advice when someone is learning to drive a manual transmission. Practice on your own, seek out an instructor, find a buddy on INGO to go with; there are many options that can get you to build up the fundamentals without the pressure, then once you've got them down start up the dates to the range again.
Here's some reading on shooting techniques and mentality. They're good for everyone to read, even if it says female in the title.
How to shoot a handgun accurately by Massad Ayoob Issue #85
Firearms handling refresher Part I: Handguns by Massad Ayoob 031207
The subtleties of safe firearms handling by Massad Ayoob Issue #103
Tailoring guns to females by Massad Ayoob Issue #131
Armed and Female by Massad Ayoob Issue #63
Women and guns by Massad Ayoob Issue #121
If you like how those are written, pick up his books entitled "Stressfire" They make look a little dated but the techniques hold true.
Take a look here at the articles under "Shooting basics"
Cornered Cat
Here are some videos from youtube that can be a start
http://www.youtube.com/watch?v=A1Cf0WEeXZk&feature=relmfu
http://www.youtube.com/watch?v=22msLVCtPk8&feature=relmfu
http://www.youtube.com/watch?v=3Xa5JPLGIsU&feature=relmfu
http://www.youtube.com/watch?v=JAni-MCJSUU
If you take a look on amazon type places you can usually find Magpul's Dynamic Art of the Handgun for $25-45, here is a trailer http://www.youtube.com/watch?v=ZTr8xvkUWp4
If you can find them, Handguns and personal defense TV have some great segments on various basic and intermediate techniques.
And all of that can provide you a decent starting knowledge base and a plethora of little tips to learn from and try to implement. However and I cannot stress this enough, you cannot learn how to shoot a gun on the internet, you cannot learn how to shoot a gun on the internet, you cannot learn how to shoot a gun on the internet; it is going to take some real practice, and you're going to need to accept constructive critique to be able to improve. Do a little dry fire every night, go to the range every week; and get some training from the professionals, on this site or ones listed around the country, every few months or every year; having a set of eyes that knows what to look for being able to teach you about it in a learning environment is when you're going to yield some real dividends. And once you get comfortable you can start going shooting with your spouse, and I'd recommend attending one of several competitions every few months as well, going up against other shooters and the timer can help you learn to "solve shooting problems" and put some extra pressure so that if you ever NEED to use a firearm, you've handled pressure and adrenaline while running the gun.
I actually do have that, i think maybe i found it here a few months ago! I like it.Perhaps this will help. My first thought was sight alignment.
Are you using the same ammo?
I understand what you're saying about shooting worse when more people are around. I was doing the same thing. I was compensating too much for the recoil so I wouldnt look like a wuss shooting .40.
Aim higher, that should fix it