The Dilhorne Dynasty Series by Paula Marshall

Society heiress: Sarah Langley came to New South Wales to get away from her stifling English home. But she didn't expect to mix with transported felons... Social outcast: Alan Kerr, an unjustly disgraced doctor, spends all his energy helping Sydney's poor. He has no time for silly society women! But feelings change as they learn more about each other--and a forbidden passion starts to grow...

What was he keeping from her? Cobie Grant made a quixotic marriage to save Lady Dinah Freville from her unkind relatives. Now he thinks he can enjoy the benefits of married life without involving his feelings. But somehow he's finding it harder and harder to hold Dinah at arm's length—especially since she has become a beautiful, assured woman. Dinah, loving Cobie deeply, fully intends to do whatever is necessary to win his love... moreWhat was he keeping from her? Cobie Grant made a quixotic marriage to save Lady Dinah Freville from her unkind relatives. Now he thinks he can enjoy the benefits of married life without involving his feelings. But somehow he's finding it harder and harder to hold Dinah at arm's length—especially since she has become a beautiful, assured woman. Dinah, loving Cobie deeply, fully intends to do whatever is necessary to win his love. A task made even more difficult when she discovers he is leading a secret life… less