Thomas kisses Eliza on a whim just before her engagement party. Between that and some of his rakish behaviors Eliza and her brother refuse to trust Thomas with Eliza's reputation, heart, or well-being.
Thomas is said to not really like children but no one really knows that he has a lot of affection for Eliza's daughter Rosa. He skips out on a ball to dance with her in the nursery and later buys her a doll.
Thomas does have a mistress and uses her mostly to make Eliza jealous. This mistress sends Eliza a single red rose with a note claiming that she'd get nothing else from Thomas.
Eliza's friend Caroline has problems with her aunt's health and needs to get out of London. So. Eliza recruits Thomas to help her get Caroline and her aunt back to their country estate. (When just before that she all but told him he wasn't enough.) He asks for one thing in return, that she wait to accept any offers of marriage until she returns to the country. Upon delivering Caroline and her aunt, Thomas ends up admitting to his love for Eliza when he blurts that he "has to try."
When they return to their neighboring country estates Eliza tells Thomas what his mistress did. Thomas writes a letter to his old mistress telling her that things are officially finished between them. He tries to properly court her and she continues to reject him (which gets rather irritating after a while). After one too many rejections there's an argument in a library including Eliza, Thomas, Eliza's brother, sister-in-law, and Caroline. After Thomas faces another rejection from both Eliza and her brother, he decides that he can't stay close to Eliza while she considers marriage to another man. He returns to London. While getting drunk one night he is stabbed by a man sent by his old mistress.
Eliza finally gets her brother's blessing to marry and trust Thomas so she follows after him, nurses him back to health and ultimately marries him. ( )

Playboy rogue has always been in love with Eliza, sister of his best friend since childhood but doesn't realize it. Now widowed, with a 4 yr old daughter, she is looking for a husband among the "ton" to protect herself and her child. Lots of miscommunication between Thomas and Eliza before the HEA. My problem with this was that the hero wasn't likeable. ( )