it's funny how the meaning of a simple little phrase can become so bedeviling, isn't it?
if you are essentially following the main DR techniques, i wouldn't worry too much about how you reply to your wife's "i love you". as long as you are replying to something she says, i don't see the harm in very matter of factly replying in kind. i think you want to avoid two things:
1) making too much of these exchanges by being too self-conscious or too clever by half
2) trying to escalate the level of intimacy that she originally offers.
as far as the much-dreaded and ever so shallow phrase of "i love you but i'm not in love with you", i would not be too concerned about it. on the one hand, "love" is both a conscious, mental thing that people can think they have or don't have. but once you really, really bond with someone through a long term, loving, sexual/romantic relationship, there's an incredible and enduring force there that the person saying "i love you, but i'm not in love with you" often underestimtes. it's why i think the DR strategies work with people who can patiently use them and don't panic.
if you look at the success stories, and you should, you'll see certain common denominators. if i could identify the single most important one, it's that those people stand back, regroup, and then make themselves more appealing without overpursuing the other party. and then, slowly but surely, that force that the "ilybinilwy" party can't see, begins to exert it's very, very potent power.
