My initial reaction is that you both don't need to stop seeing your OSOs, for several reasons.
First, she doesn't want added pressure. Being monogamous, even temporarily, and focusing on making it hot again between the two of you would seem like a big pressure to me. You might tread carefully and think you're not pressuring, but, it's just too much of a heated topic to not feel on some level that letting go of the OSOs means there must be improvement in this area. Pressure! I think that just finding ways to connect again (on many levels, not just sexually) will be a big help, without making this such a "heavy" issue.
Second, and no less important, it would be disrespectful to your OSOs to ditch them in favor of working on your relationship with your wife. When you get involved with several people, don't they all deserve the same respect and consideration as human beings whom you love and care for? I think it's is a responsibility in poly to not take any of our relationships lightly, and discarding one for another seems to send a message to the OSO that they don't matter. That doesn't mean that your wife doesn't hold a special place in your heart, nor that she can't have special treatment as your primary, but each person should be accorded the respect and honor they deserve as a partner in your life.
I think it would be better all around for both of you to continue connecting in ways that you enjoy being with each other, keep communicating, and bring respect, kindness, caring, and love into all your relationships.
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "