Assalamoalaikum,
i have been married since last four months and after marriage i found that my husband(who happen to be my first cousin too) is involved in smoking(3 to 4 ciggrates a day) & eat tobacco too once in a day...evry time i asked him to stop it & told him that it is forbidden in islam..but he doesnt listen to me...and he said its not harmful to my health nor it is completely forbidden in islam...
since i hate his smoking & eating tobacco habit & in addition i m worried that its not good for him too as he is a patient of hyper tention...will he be sinful if he is not listening to me regarding this issue???...what effort i should make in islamic way to make him deprived of this filthy habit???..as i have already politely talked to him many times & tried making him understand that it is not good for him health wise & religion wise too...please advise in the light of islam.
ma' salam...

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Smoking is prohibited under Sharee‘ah for many reasons which are mentioned in Fataawa 81345 and 81589. If your husband smokes cigarettes and chews tobacco as you mentioned, he will be sinful. Tobacco is the source of harm in smoking or whatever contains this substance.

In fact, you have done well by advising your husband politely regarding this matter, and we advise you to be patient with him, keep on advising him and supplicate Allaah The Almighty to guide and reform him. Perhaps Allaah will guide him to repentance. No doubt, supplication is one of the effective weapons of the believer. Allaah The Almighty Says (what means): {And your Lord Says, "Call upon Me; I Will Respond to you."}[Quran 40:60]

Besides, seek the help of some of his relatives or virtuous people whom he respects. You can show him the two Fataawa mentioned above. Also, you may tell him some real stories or health studies that may help you convince him to quit smoking.