For the growing legion of repeaters, a talkfest on the problems of remarriage; and what isn't? Reminiscing is out, spouse number two doesn't want to be reminded of number one. Stepchildren are impossible: ""One either works out a rapprochement. . . or watches a marriage erode."" An equal impediment is money--the first wife's revenge, the husband's atonement, the second wife's bitter pill. And while you're swallowing that, you may both be assaulted by The Wife Who Won't Let Go. But sex is apt to be better, and given the more relaxed and tolerant attitude possible on the part of both partners, remarriage can work. The confidences of assorted Hank F's and Connie V's--punctuated by comments from (chiefly) psychiatrist Norman J. Levy and matrimonial lawyer Raoul Lionel Felder--may have a certain purgative value; and if it all sounds pretty hopeless, well, says author Reingold, people who divorce and remarry tend to be optimists.