Before you commence complimenting her (because that was one of her complaints about you), have a heart to heart with yourself about all the reasons you want to do this. Is it mostly because you want to be a better version of yourself for you? Can you do this with no expectations back from her? Is it to make her happy and keep her from leaving?
What if you stop complimenting her completely and she leaves the marriage. And she tells you that is the reason. What have you lost? Do you think it’s healthy to give up on a marriage because someone does not compliment you enough? Is that how unconditional love works? What would you make of a grown woman needing complimenting to this level?
Have you ever read No More Mr. Nice Guy?
Me 41, H 47, M 15 yrs, S11, S13 BD 1: 11/4/14 we work on it; really I pretzel myself BD 2: 3/31/15 H goes down to "dorm room" 8/15: H back to MBR 10/15: H back in dorm room 1/18: H files, now divorced