I just replied on your other thread - what I would say is the idea of managing alone is worse than the reality. Do you know what aspect of it your wife is frightened by? I was quite frightened at the prospect of keeping them staggered on feeds so I could feed and change them one at a time, and dreaded them both always needing to be fed at the same time. It's OK once you get started - feed times can be more flexible than you might think. Get a notebook and jot down feed times, and then you have an aide memoire for when to aim at for the next one.
Also, I assumed I would never get out of the house with them during the day, or at least that each outing would be like a polar expedition. The first few days or outings can be difficult and awkward while you find your feet and get to grips with buggies, but you quickly get adept and your wife should be encouraged to be confident enough to give it a go. And in fact it's really important to get out of the house with twins on a daily basis.
If she starts with a walk to the shop to buy a loaf of bread, the worst that can happen is you mess up the timings and find you're in the queue to pay when one or both of them decides he's hungry. So then you hurry home and feed them, possibly with lots of screaming, but it's not the end of the world if they cry. Stressful to hear, but in the scheme of things not a huge problem and it doesn't mean you won't get it right next time.
And when you do get out and about, you will have strangers come up to you and admire them, and frankly admire YOU! If you feel that you haven't got a clue what you're doing, you will get an instant ego boost from people saying how cute they are and how they wouldn't know how to deal with two babies.
Maybe it would help if a friend/relative could come and spend the day with your wife, but on strict instructions only to be in the room and not help her unless things get way out of hand? If she has the safety net but tries to get through the day dealing with them herself, she's got the chance to see what works and doesn't work, maybe have some helpful observations from her friend and build up her confidence. And if you haven't already, maybe buy her a present and card from the twins calling her the best mummy in the world - silly but it does help you feel they're happy!
I hope this is helpful. It's really important that you both feel able to manage them on your own sometimes, but as for the socialising specifically well things have just changed hugely. Your friends must realise that, and you will be back in circulation at some point - provided that your wife does begin to feel confident that she can manage on her own for a whole day.