When I was studying in college in the United States I noticed that besides the language, American students differed from Russian in one thing: they did not let each other copy papers and they did not do each other's assignments. My Russian mentality could not grasp why.
When I was at school in Russia it was "natural" for students to whisper test answers to each other and pass the cheat sheets along. I could not imagine my friend not helping me with my physics tests. He was good at it, I was terrible and since we were friends it was not even discussed that he should help me. I, on the other hand, was better in languages, so I wrote a number of compositions and checked quite a few papers for him.
I did not even think it was dishonest and I did not feel bad doing what we did. I knew that if after graduation he would need to write a cover letter or even a love letter to his girlfriend, I will be always there to help him. The same way I knew he would help me with math or physics.
I did not have any friends (the way I define friend) at the US school, but I noticed that people who claimed to be the best buddies did not copy each others papers and did not do each other's homework.
Back then I did not really know American culture well, so I could not understand why friends do not help friends. Now that I understand more (or at least I like to think so), it makes sense to me. In American culture you have to rely on your own abilities and strength, so if you do not learn how to write a paper properly, your classmate friends are not going to do it for you later in life. They may for money or for some exchanged favor, but they are not going to do your work for you just because you are their friend. Even if they are really good at what needs to be done.
Russian friendships are intense. It takes months or even years for Russians to become friends, but when they do, they become like a family. A friend is not the same as a drinking or a dinner buddy you meet once a month and discuss a new brand of chips with. A friend is someone who will lend you money when you need it; listen to your problems and let you pour out your soul. A friend is someone who will do anything for you, but who also expects you to be there for them no matter what.
Russians rarely go to psychologists or psychiatrists, because they have friends to talk to and to help them solve their problems.
If you are stuck at the airport or need a ride, and your friend has a car, he or she will be happy to help you out and I really mean "happy" when I say it. When we went to Russia for the first time, we needed a ride from the airport to the city where I used to live. I did not want to bother anyone and I got Americanized a bit, so we just hired someone to take us home. When my Russian friends, a married couple whom I have not seen in person for more than 2 years, found out about it, they got really offended. "Why did not you call us?" the guy said. "You do not trust us or something?" No, they would not have accepted any money and I doubt they would even let us pay for gas. They were (and are) just true friends.
In comparison, once my husband was away for a business trip and I needed some help with my parking light (I wrecked it by accident in our backyard). I called him; he called his friend of 10 years (his best friend by the way) and asked him to come over and take a look. The friend (who was 5 minutes away) came with some red tape and put it on my light bulb (which was not damaged by the way). It took him less than 3 minutes. I ( "jokingly") told him that I do not have any cash, so I can not pay him right away. He said: "No worries, when your hubby gets home he can pay me back by taking me out for dinner". And to my surprise, that's what happened, so the 20 cents which probably was the cost of the piece of tape and 3 minutes of time cost us 20 bucks.
Again, I am not saying the Russian way is better than the American or vice versa, but things are certainly different and it may be difficult for people from both cultures to make friends and maintain friendships. Finding a balance takes time and effort, but I believe that it is possible. Do not push your Russian wife to make friends, because it is not as easy for her as it may seem and do not be jealous or suspicious if she calls her friends often and tells you how much she misses them. Time will help her with both.