In Jainism there is no concept like “haram.” That term is from other traditions. So falling asleep as a passenger in a car with your fiancé is not considered a sin in Jain teachings.

What matters in Jain Dharma:

• Ahimsa (non-violence) and respect for others: be mindful and considerate of your fiancé and others on the road.
• Brahmacharya and householder ethics: ascetics abstain from sexual activity, but householders are allowed to marry and have a loving, faithful relationship within marriage.
• Satya (truth),Asteya (non-stealing), Aparigraha (non-attachment): maintain honesty, avoid harm, and keep modesty and self-control in your relationship.

So, there’s no religious prohibition here; focus on safety, consent, mutual respect, and living according to ethical principles.