Love comes after sex. This is one of the things that's most radical and shocking about Lady Chatterley's Lover. There's no "First comes love, then comes marriage, then comes Connie pushing a baby carriage. And with that, Lawrence flies in the face of hundreds of years of tradition. He insists that you can't have love without sex, and you're fooling yourself if you think there's any such thing as a sexless marriage. Love is the way that sex expresses itself, and not the other way around. This is why Lawrence wouldn't want you heading out to have a bunch of meaningless sex—because meaningless sex is mechanical, and being mechanical is the worst thing you can do to your body.
Lady Chatterley's Lover is fundamentally cynical about love. The book seems to suspect that there is no such thing as true love.
Love and sex are inseparable. It is impossible to love someone romantically without having sex with that person.