In the clay target games - Skeet, Sporting Clays and Trap - Trap is unique in that 100% of the time it is a "rising target". Skeet and Sporting Clays typically have more crossing shots / not just rising targets.
In general - "Trap" guns tend to be heavier and longer. " Trap" guns tend to shoot a little higher patterns ( like a 60%/40% or a 70/30 over point of impact) because most "Trap" shooters like to float the bird over the bead ( so they never lose sight of the target ) and they need a little higher pattern to do that. In general - "Trap" guns tend to be heavier and longer ( 32" or 34" Over under or single barrels ) because the sight plane being longer helps a little and the extra weight ( around 10 lbs ) helps smooth out a swing and give you better follow-thru. There is less left to right barrel movement in Trap - than Skeet or Sporting - so the heavier gun is not a dis-advantage.
In general - Skeet and Sporting Clays guns - tend to shoot flatter ( 50%/50% pattern ) - be a little shorter 28" or 30" barrels - and lighter ( around 8 1/2 lbs )...
You can shoot all 3 games with any gun you want - pump, semi-auto or Over Under. At Trap especially - since its usually singles - there is no disadvantage to shooting a pump gun. When you have pairs of birds in the air / most shooters would want a semi-auto or O/U.
The most versatile "Trap" gun in my opinion - is the Browning XT with 32" barrels with an adjustable comb ( so you can move the point of impact up or down and side to side ). There are single barrel Trap guns - Browning BT 99 or the older BT-100 and they're both great guns / but not for a rookie - they are very specialized in my opinion - and while I have some of both - I shoot the O/U Browning XT a lot more for Trap. The XT just feels right to me - weight, balance, swing, etc ...
http://www.browning.com/products/cat...-comb-firearms
New, the Citori XT Trap is around $ 3,000 - but I see a lot of good used ones for around $2,000.
If you want a "Lifetime" gun - it means they better stand up to at least 100,000 shells without any major issues - most of the guns in the Browning Citori lineup will do that ( but there are about 30 different models ) - and the only Citori, I consider a Trap gun is the XT Trap or the BT-99 or BT-100.
A more versatile gun - than the Browning XT Trap - in my opinion is the Citori XS Skeet model ( in 28" or 30" barrels, with the adj comb ). Its a very good Skeet and Sporting or field hunting gun ( in my opinion ) - and not a terrible Trap gun. New - its about the same price as the XT Trap...
http://www.browning.com/products/cat...-comb-firearms
The question is do you really want a "dedicated Trap Gun" or something more versatile...
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Very few ladies are going to like a 32" O/U that weighs 10 lbs ....its too long and too heavy. If you're really searching for a gun that both of you can shoot / I think it means a gas operated semi-auto -- like the Beretta. I would not go with a "Trap" version --- most any of the Beretta's will be fine. But Browning makes a Silver Hunter that is not a bad gun ....and there is Remington, Winchester, etc .....
My wife doesn't shoot / she is very strong - but 5'10" and 115 lbs with small hands ...where as I am 6'5" and 280 lbs ....( with large mitts ) ....and its going to be very hard to pick 1 gun for both of us / or for you two probably.
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If you really want a dedicated Trap gun / but an XT for yourself ....and buy a nice semi-auto for her to shoot ....that you might use for Skeet or Sporting Clays ( unless she wants her own gun ) ..... realistically about $4,000 will get you both guns new / maybe $ 3,000 used. Respectfully, I think the gun your buddy is trying to sell you is a mistake / priced too high - and not the most versatile option for you.