There's a lot of entrapment in Lady Chatterley's Lover. Connie is trapped in an unhappy marriage; poor Clifford is trapped in a wheelchair; and Hilda, Connie's sister, is trapped in a prison of convention. There are all kinds of traps—marriage, family, convention, money, fate—and the novel doesn't give us any real sense that it's possible to break out. Connie isn't free at the end of the novel, and neither is Mellors. Even divorce isn't necessarily a way out, as anyone with joint custody can tell you. We're all trapped together in a world that's basically a prison full of lunatics and weaklings. Awesome.
D. H. Lawrence suggests that the worst kinds of prisons are the mental ones. Physical limitations mean nothing if one's mind is free.
Lady Chatterley's Lover rejects marriage as a societal prison. It implies that Connie and Mellors should not marry.