We never stop learning new things, even in our mother tongues. And when we reach a satisfying level we can either just enjoy the language, use it and maintain it and use our free time for other hobbies. Or we move on to the next language. There are 7000 languages in the world. Enough for a thousand lives. ;)

We need to understand that "learning" is a process, not a goal. That's why people say, "Learning never ends!" Even if it was one language instead of 7000+ languages, we would never get perfect in it and would be learning something new every now and then. 

@Sarah

What do you mean by "even though this site was created for it"? Italki was not created for being just a place to study Business English. It was first a language exchange community and then was made into an online teacher market place. But not specifically for English but all languages.

Some people quit learning after the wedding..lol

Language exchange community. ...sounds good, but noone would create a site without perspective of earning some money, isn't?  The site doesn't really care about the community and it's safety. But I wouldn't like deepen in this thoughts..
I wish good luck to all Ukrainians in Poland hehehe :) but I think they would rather focus on English than Polish, as polish people speak English very well in all areas of life nowadays. But this is theme for some other discussion topic.

What I mean is clearly written above..no offense