Do you live in company provided accomodation? If so, others in the accomodation may almost certainly be aware of the lack of marriage certificate. Problem? Only if someone (a) takes exception to your "arrangement" on religious or moral grounds (b) you tick somebody off. There are a lot of vindictive busybodies in company accomodation who would be glad to "dob you in" - result, arrest, jail, deportation.

Does it happen to white westerners often? No. But the possibility exists.