As a woman who normally only orgasims once (and pretty hard and long at that)I understand your wife's frustration. Often I've had to suppress the urge to climax in order to keep going.
Once the O is on me and washed over me, sex isn't quite the same as it was before. Still pleasurable, still fun, still wow....just not in the same way as it was on the climb up.
I've spoken to K about my desire to be multi-orgasmic on several occasions and he understands. He's always quick to remind me that he likes me just as I am and doesn't need me to be multi but he's a willing participant in any practicing I might want to do!
And so.........To the point! If your wife is one to take while and it sounds as if she is, try a lot of internal stimulation without messing about too much with her clitoris. Have her tell you when you're on a spot that is working for her and keep at it. Combine that touch with other activities like kissing and breast stimulation and she may find herself with a feeling like she could cum. Or a feeling of a much reduced orgasim (is that spelled right?). As long as she stays aroused the big finish will still happen but with a lot of good feelings well before then.
For me this works out particularly well because in certain positions K is hitting that same spot so that when we're ready to finish we can switch around into a position that allows both of us to finish. It also intensifies my orgasim to a point where I've been known to 'squirt' a little.....and did THAT ever come as a surprise!
You may also want to talk to her a little bit too about relaxing and not putting pressure on herself to either cum or to hold off. Let your experimentation happen as it will. This isn't always easy....letting go and just not concentrating at all, to remain only in the physical. It is achievable however with a little practice.
Just as an aside.....When you're accustomed to the BIG orgasim it's sometimes hard to recognize the smaller ones. For me it's the same feeling as when I'm just starting to peak.
Keep talking and trying new things, put no pressure on yourselves and let things go. Might be surprised with what happens.
