Paris
Capulet never said he didn't want Juliet to marry Romeo. Nobody ever suggested the idea to him. As we hear in Act 1 Scene 5, Capulet has a pretty high opinion of Romeo as it turns out, and he might have reacted positively to the idea. His attitude was not that he didn't want Juliet to marry Romeo so much as that he really wanted her to marry Paris.
By comparing Paris to a book, Lady Capulet encourages Juliet to consider him as a potential suitor for marriage. She uses the analogy to suggest that Paris is a suitable match with good qualities that would make him a desirable husband for Juliet. She hopes that Juliet will be receptive to the idea and ultimately agree to marry Paris.
The first character to mention the idea of marriage in "Romeo and Juliet" is Lady Capulet, who discusses the prospect of Juliet marrying Paris with her daughter.
He decides they should get married.
Capulet has no idea that Romeo had married Juliet or that he even intended to until after they both were dead. At that time he was of course unhappy that Juliet was dead, but felt that he would rather have her alive and married to Romeo, who he agrees to build a statue to.
Juliet does not want to marry Paris, but she has to otherwise Lord Capulet will disown her.
Juliet says she hadn't thought much about marriage."It is an honour that I dream not of." She is open to the idea though."I'll look to love if looking liking move."
When Capulet says "Death is my son-in-law," he is referring to the idea that death has taken Juliet as his bride, meaning she has passed away. He is expressing his grief and acknowledging the finality of Juliet's death.
In Act 1, Mrs. Capulet approaches Juliet with the idea of marrying Paris. But she has never been one-on-one with Juliet in a discussion of this importance, and is unsure of how Juliet will react. She wants the nurse nearby for moral support, as the nurse knows Juliet better than anyone.
Juliet is supposed to be 'the perfect daughter' and do exactly as her father says. When she refuses, Lord Capulet is angry that he had gone through the trouble of finding her a husband and she won't agree to it.
Juliet's family is very patriarchal. Lord Capulet is always telling his wife and daughter what to do as if they were his servants. He also decides that Paris is going to marry Juliet without Juliet even being in the room! He shouts at Tybalt and the nurse, even Juliet! He is not one to be reasoned with and it is clear he likes to get his own way as we see in Act 3 Scene 5 of Romeo and Juliet.
At first he doesn't think it's a good idea because she's too young and is his only child, but if Paris can sweep her off her feet when he has the ball then yes. The first time Paris offers for her hand in marriage Capulet says if he can sway her to love him Paris may marry Juliet. The second time Paris offers for her hand Capulet accepts on Juliet's behalf and sets the wedding for Thursday of that week.