Main Lead forces other Main Lead to marry them

Doesn't fit your bill to a T, but have a look at Sealed with a Kiss and Loving, Never Forgetting. 

In Sealed male lead forces the female to be his mistress. They live together, but aren't married. There's a kind of passionate love/hate relationship between them with lots of 'forced seductions'.

In Loving, the couple will get married before the end of the drama.

You may like Lady & Liar. Here's what it's about, without spoiling it anymore than the synopsis does on mdl: the male lead, Bai Lang, a wealthy squad leader, falls in love with the female lead, Jiang Xin, and within the first two episodes I believe. However, she's already in a relationship with somebody else. Jian Xin is poor, but she discovers she is an heiress, and right after she gets into an accident and loses her memory. Bai Lang, desperately in love and aware he had no chance with the old Jiang Xin, takes advantage of the situation and lies to her, telling her she is his fiancé. Little by little though, she gets closer to the truth. It has the three bonuses you listed, only they live together engaged, not yet married! I think it's more or less entirely subbed on viki :) (I haven't finished it yet, cuz when I picked it up the subbing stopped for a while, but from what I see they've almost finished it now)

I also second Sealed With a Kiss. It's not exactly the same plot you're looking for, but the male lead forces the female lead to stay with him like no other drama character I've seen so far. I found it a bit too cruel though, so I gave up on it.

Cruel Romance - This might not tick all the boxes, never the less a very good drama. Rich Guy, Falls in love with the girl at first sight, lots of cute scenes with the main leads.

A Thousand Years of Love has a very possessive male lead in it who forces the main girl to be with him. I'd say it fits all your criteria. Birth of a Beauty also has a male lead whose pretty obsessive but he doesn't try to force her to marry him, he threatens her multiple times though.

In My Heart Twinkle Twinkle the lead guy manipulates the girl into marrying him early on in the drama. However it doesn't have everything you've asked for.

General and I - Bai Ping Ting a remarkable woman with strategic skills. She has someone who love her and want to marry her. But everything changes as the general Chu Bai Jie meet her. He loves and is obsessed with her. She try to escape... but is she able to withstand for ever?
(I really loves this couple!!!)

Lady and the Liar is exactly what you're looking for, she's actually a rich heiress but she got lost as a child and was adopted by an elderly man. She saves Hawick Lau, he later forces her to marry him but he gets rejected as she is already in love with someone else. Later an accident happens and she loses her memory and Hawick takes advantage of the situation