I can't say about his wife, but my beloved not only bought the game, she loves playing it as well. (I'm the luckiest man on the forum.)
Or, at least tied for luckiest. I have a wife and two kids (17 & 23) that all game, so I can agree it's a great way to live.
Dangerous terrain is questionable for the game. Warfare adds silly rules for deadly barbed wire, but that's about it. You could try and house rule porting over whatever you liked from Warfare, but it would be simple to simply add your own if you really want it.
Make a 'deadly' terrain space a 1/x attack for a unit moving through it. You could make it more realistic by making the space immobilize a unit, rather than destroying it (having done maneuvers through many swamps, snow and deserts without ever seeing a casualty due to terrain, it should be rare). An infantry unit that gets a any hits could lose movement points equal to the number of hits before they could move out, or have to make a roll of a blank for an action to get free for easier tracking (I suggest a blank instead of a hit because infantry has been dealing with terrain for a long time). A vehicle could either be immobilized for the rest of the game, or have to roll each turn until it got a hit to free itself while staying in the square. Either unit could either fight, or try to free themselves.
You could give variety for vehicles, perhaps making heavy vehicles roll a blank to get stuck, and light vehicles a blank to free themselves, or roll dice equal to the vehicle's Armor to see if they get stuck. Getting unstuck could be more difficult, with light vehicles rolling one dice, and needing a blank (or hit) to get free, medium vehicles rolling two dice, and needing all blanks (or all hits), and heavy vehicles rolling three dice, and needing all blanks (or all hits). That would give you a lot of variety, because you could assign varied restrictions (hits or blanks to get stuck or freed) to various terrain to give lots of terrain problems. If you had a GM for the game, neither player could know the effect of different terrain.
Rules for forests have already been published on the forums, so I won't reiterate them.
Barbed wire is not deadly, but it does slow down infantry units that don't know what to do about it. You could treat it the same way as the terrain option I noted above, and it would make a good fit for infantry, though vehicles would be immune and destroy any barbed wire they moved through, rather than be immobilized. Barbed wire does not have the tensile strenght to stop several tons of vehicle moving through it. Star Wars had 'miracle wire' in The Empire Strikes Back to drop the Imperial walkers, because that light a cable would not be strong enough to stop that much mass. Barbed wire as a deadly obstacle was one of my many disappointments with Warfare.
Infantry trenches or foxholes would be hard cover for infantry, but not a problem for vehicles. Anti-tank trenches could be impassable terrain like anti-tank obstacles, but without blocking any line of sight, so they would also give infantry hard cover. You could even let the infantry dig grenade sumps in their trenches and foxholes, and give them cover against grenades, though I'd recommend that costing a point or two for the force that added them.
Rubble could be normal terrain for infantry, but cost a vehicle two movement to enter unless they can jump. Lots of rubble could make jumping dangerous, with a roll to damage the jumper on landing (anywhere from a 1/1 up to a 3/1 attack when jumping into the space), and the damage could restrict just vehicles, or vehicles and infantry actually jumping to get into the space.
Those are some simple terrain rules, and so long as all of the players involved know before the game begins, they should be easy to work with.