Someone asked the marja`:
What is the ruling in the Revealed Law regarding mingling with and sitting with the in-laws of either the husband or the wife? Is it permissible for the husband to be to wear a ring for the engagement before the sacrament of marriage has been made? May Allah reward you with every good in answering this question.
The marja,` Imam `Abdur-Rahman ash-Shami, may Allah preserve him, said the following:
This form of mingling is not permissible and the means to it is also not permitted. You should take steps necessary that are possible for you to make sure that this does not happen. As for the engagement ring, you are also not permitted to wear this as the woman is not your wife yet.
Taken from the website of the maraji`