Light Yagami never fell in love with women. They were tools that could be used whenever needed in his own twisted or perhaps logical mind. Sometimes women were a burden to the great Kira, but if proven useful...rewards could present themselves.
Yuri had been useful in the very beginning. She was only used once, to find out who was following him and why. Using the bus jacking as an excuse to get a look at the identity, he was able to reward her with a day in Space Land. He managed to get her to keep quiet about it easily by calling it a secret and most special day.
Misa was the most convenient woman he could have asked for. She would do anything and everything all for the sake of a kiss or a date. She was able to be a bit less capable in the intellectual, but useful at the time. He would have been able to actually destroy her if it weren't for Rem. Rem apparently had feelings, unlike the great human god Kira. Threatening to kill him if he ever wrote Misa's name down was a factor he couldn't simply ignore.
After all, she was a shinigami. Even though he eventually killed her, he still had to deal with the attention grabbing wife Misa Yagami had become. Certainly it was a great idea when he lost one death note to L's possible successors in the Wammy House. The only blessing he seemed to have when it came to his dear blonde wife, seemed to be choosing to trade for the shinigami eyes twice. Her loyalty always remained, despite the fact he had never loved her.
Kiyomi Takada had been an accident in itself. He had been backed into a rather tight corner at the time, unable to order his Kira replacement at the time. Teru Mikami had even requested his help at the time. One blessing, other than the intellecutal part of the rather ambicious replacement, was the fact he had chosen one of his college pawns. At the time Kiyomi had only been a distraction factor for L to notice.
When she had become Kira's spoke person, it was a change that was greatly appreciated. It was simple to be able to get her to fall hopelessly in love with him. With even better luck, he had been able to finally speak with his disciple. He rewarded Kiyomi in the end with her death, since she had finally rid him of Mello A.K.A Miheal Kheel.
Light Yagami never loved women. It wasn't that he had no capacity for them, but they were just tools. Tools with a lot of emotions he could use to his advantage. So was the way of Kira.