Why does god say "be fruitful,?

God never made sex an impure act. Sex itself is a wholesome act. God set rules for having sex. It should be with one's marriage mate (a man and his female wife) in a dignified way, not in unclean ways. Sex is not for those unmarried or outside of marriage of another person. Rules and regulations keep human order and peace.

Improper sex is called fornication. This causes selfishness, idolatry (idolizing sex), promiscuity, perversions, unwanted pregnancies and children, emotional and mental anxiety and stress because of the lack of love, murders, betrayals, abortions, child neglect and abuse, sexually transmitted diseases, addiction to sex, objectivity of the human anatomy; especially men toward women, moral breakdown of society and much more....no wonder God hates fornication...it is very harmful to human life. :(

With you're husband or wife.

Sex in Islam is not impure infact it is encouraged between a man and woman who are married.

Neither can say no to the other if one wants to have sex unless it's for a good reason. If no sex or lack of sex then the other might start looking else where for pleasure.

It was NEVER an impure act. it's a glorious act but it is a powerful one and needs limits to reign it in. God knows this, and created the laws governing it. It protects each individual, potential children, and society as a whole.

Matrimony, which has as one of its prime objects to create children, is a sacrament. Sex between married partners is therefore sacred and not impure. The misuse of this sacred act is what's impure.

He said that to Adam and Eve and again to Noah and his family in order to jumpstart the human race

Today, there is way too much multiplying

So much in fact that fifty million abortions have occurred since Roe v Wade

it's only an impure act between unmarried people

You have to eat the daily recommended amount of fruits or else you will die young and your not yet wrinkled flesh will rot underground and get eaten by worms and maggots. But if you get cremated..... Then you will just be a pile of soot.

I suggest you don't take that risk and eat some fruit.

He's into BDSM so he can punish you for an eternity.