Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Gifting is an Islamic manner that is highly recommended by the Prophet (peace and blessings be upon him).
2- However, giving a gift to someone should not prevent the others, such as one’s heirs, from their legal rights.
In his response to your question, Prof. Dr. Monzer Kahf, Professor of Islamic Finance and Economics at Qatar Faculty of Islamic Studies, states:
From the legality of the Shari`ah, it is permissible. But any action has other aspects too. If he has children and/or parents and he intends by giving you the house preventing them from getting any part in it should he dies, giving becomes haram by this intention.
Also, if a man is a polygamous husband (marrying more than one woman), he should make justice between them in giving and gifting.
Otherwise, when there are no ifs giving a gift to one’s wife is a great rewardable by God loving act.
Gifts between Muslims, especially husband and wife, are always loving gestures as mentioned by our beloved Prophet (peace and blessings be upon him).
Allah Almighty knows best.