I think my husband still loves his ex?

They have a daughter together which was a result of an affair she held with my husband for 3 months. Which my husband claims he knew nothing about until she became pregnant and had to admitt to her husband and my now husband that she didn't know who the BD was! This happened in 2003 immediately after finding out the truth my husband left her alone and soon after in 2004 we met and were soon married. Once the child was born she contacted my husband went for a dna test and it ended up being my husband's. We had problems due to that and they got closer which resulted in them sleeping together again even when she knew about me. Well lets cut it short they haven't had contact since 2006 but he continues to bring her up he doesn't even talk about his estranged daughter as much as he does about the mom....... what to do? Totally lost and confused...