It is not possible to prove what your reasons were for marrying someone. To marry for financial reasons is not fradulent. It is not a criminal act per se, but it can be grounds for divorce. If sufficiently proved it can also invalidate a prenuptial agreement and/or be grounds for a civil suit if financial damage to an "innocent spouse" or the spouse's heirs resulted.
I don't understand your question. Marriage fraud to violate immigration law is illegal and a felony. It is illegal to marry someone to make them legal. It is not illegal to marry an illegal immigrant because you love them. It is not illegal for you to immigrate your illegal spouse...assuming that the marriage is legitimate. It is illegal to mar them.
wants financial security
No, due to fraud.
Any American can marry any non-citizen, but selling marriage and citizenship is illegal. Financial circumstances are not a factor in legality.
Same-sex couples should not marry if they do not love each other. They should not marry solely for money. In short, the reasons for not marrying are the same for same-sex couples as for any other couple.
No, that is known as BIGAMY, and is against the law(at least in the US). If the purpose of the US marriage was to gain American citizenship, that is FRAUD and is a federal offense.
You took an oath that you are free and that you will marry him/her. It is a conditional visa. You brake the law if you do and really is fraud. Go back, do not get married and wait for your new love to call you back....
No. If you remarry before your divorce is final, then that marriage will not be legal, and you could be charged with bigamy.
He married Anne of Cleves for diplomacy reasons.
She thinks that something supernatural happened to them
If you still meet the financial limit and are considered disabled
Your fiancee would have to marry you, your fiancee cannot adjust status if there is no marriage. It is better for her if you tell her before she enters the U.S.