SPOILERS FOR EASY FREEDOM - PLEASE DON'T READ ANY FURTHER IF YOU DON'T LIKE SPOILERS
OK, this is for those who absolutely HAVE to know what happens. People have asked me to go into a little more detail, so I will.
I'm warning you, there are spoilers below this point.
Dev and Cathy do get married.
Chris is still in love with Cathy so he causes as much trouble as he possibly can which is quite a bit. For instance, he flirts with Julie and sleeps with Julie just because he can't get to Cathy.
Both Dev and Cathy are as easy to manipulate and as emotional and messed up as they were in the first book and the number of misunderstandings is heart-wrenching.
The "mystery woman" who totally stuffed Dev around is - Charis. There's a whole back story about her - she's a rich girl out for kicks and not a very nice person. Chris took her over after she dumped Dev and punished her for treating Dev like dirt. Chris acknowledges at a later point though that his revenge on Charis cost him Cathy.
Some of the trouble that Chris stirs is as follows:
Cathy has the baby, which causes its own set of misunderstandings. To make her jealous, Dev brings home some girls, breaking his express promise to her that he would never do that. Cathy leaves, Dev falls apart and so does Chris.
Cathy goes off on her own to paint, leaving the baby behind with Dev and she becomes more and more removed from life. Dave Hampton, who has become a friend, hangs out with her and then Janey Adams, who is Dave's ex, and made jealous by stories told to her by Chris Carter, shows up to find out who Cathy is. The two girls becoem friends and because they're both emotionally needy and confused, they become very close.
Things get worse, Dev gets more self-destructive, Cathy becomes more and more remote and Caleb begins to worry for her sanity even though he believes her paintings are a work of genius.
Eventually - Dev tries to commit suicide. Cathy wakes up and through that strange connection she has with both Chris and Dev she guessed that something is wrong. Chris, too, is aware that something is wrong.
Big Spoilers
Dev doesn't die, they pump his stomach but the attempted suicide brings Cathy and Chris to their senses. They both realise that they all love each other but that Cathy and Dev have a bond that Chris can't break. Cathy realises that she does love Dev and that she needs him to share the darkness with but that the violent start to their relationship almost destroyed their chance at happiness.