Wedding flowers can never look 'fresh' forever.
You shouldn't frame fresh flowers, they will put a high amount of moisture in the package, and just deteriorate and rot away quite quickly.
We do a lot of deeper style convex glass and display cases for numerous specialised 'flower ladies', and without a doubt the best options are . . .
Freeze drying. The flowers are sometimes photographed (for reassembly purposes), disassembled, freeze dried (takes up to 2 weeks), reassembled in flat form on mats and backings, framed (in shadow box or under convex glass).
Yes, this is a highly specialised field, but the flowers look great for a long time.
Colours are better retained when freeze dried.
Silica gel drying. Same as above, except drying with silica gel crystals. Usually disassembled posie flowers are covered in crystals inside Tupperware or similar airtight containers for around 2 - 3 weeks.
The flowers usually lose more of their colour with this process, and can be damaged by the crystals when covered.
Another option is drying as they are with stems, and either :
Clamping the stems high, cutting off stems close to clamp, framing in shadow box or under convex glass with short stub of stems held through front hole in a suitable depth double box. A lot more work and still need a box (deep or shallower) either way (flat or convex glass).
OR . . . Use a display case that sits on a table or shelf, with a flower spike rising from the base.
We do these in glass (plain or UV blocking), and UV glue a flower spike into a full glass base, or glue the spike into a stained timber base.
The flowers slide on the spike, a few petals scattered around the base for effect, then the top is placed on, finished.
Sometimes, a glass (or -ugghh- acrylic) display case can be the best way to display anything that is too bulky or impractical to be framed to hang, or that just suits horizontal form better (baseball caps, larger sports balls, model cars, etc etc).
There are generally UV options for all the above.