Which kind of brings us back to teach English or start your own business, those are the options.
If you use your brain a little there are so many more options...same for Polish people who live in UK. I know many people who are educated to very good standard yet are working in pub/restaurant in the UK. They are afraid to try for other jobs as they don't have fluent English.
A little bit of belief goes a long way, English teacher and starting your own business are not your only options, many skills are transferable, you just need a little Polish language and "a set of balls" to push yourself to do it.
My friend also has boyfriend from UK (Ireland), he buys cars and fixes them (he is mechanic) and sells them, people got to know he is mechanic and now he is fixing many person's car for them as also selling. He makes good money also.
Don't listen to negativity, if you want to be with her and have half a brain you will find something to earn money. My boyfriend loves to meet with other British guys for beer and chat so if you want ideas come Warsaw and he will tell how he lives here.
Too many people pigeon hole themselves in the career they did already, there is much more you can do.