What is the religious ruling on establishing an 'urfi marriage relationship with a girl with the intention of future marriage, while refraining from sexual intercourse and limiting it to foreplay until financial and age circumstances permit an official marriage?

If there is no valid Nikah (marriage contract), whether customary (urfi) or official, then what occurs is zina (fornication/adultery), which is considered one of the major sins. The obligation is immediate repentance by abandoning the sin, regretting it, and resolving not to return to it, in addition to severing ties with the girl and closing off all avenues of temptation. The mere intention to marry does not lessen the heinousness of the transgression, and youth is not an excuse for committing what is unlawful. The solution is marriage for those who are able, or fasting and lowering the gaze for those who are not, along with abundant supplication and keeping good company. However, if there is a customary Nikah contract that fulfills all conditions, it is valid even if it is not officially registered. But if a condition, such as the woman's wali (guardian), is missing, then the contract is void.