I have one that might help. Changing your
action/reaction to your spouse when they do it. I don't know the characteristic so I will choose one at random.
Let's pick flirting(a really annoying habit)
Change your
reaction(put it in your head) that your spouse is flirting for your benefit and trying to gain attention from others to impress you and meet your expectations of sociability/attraction etc.
Change your
action to one of assurance, let them know you love and care about them.(I've actually seen this work to the point ending the bad habit)
There are other methods to use if
action/reaction doesn't work so don't give up hope. But give this one a real shot, follow through(in your mind first) with your chosen action/reaction and see if it helps ease your mind a little, if it does not, try another one in your head til you find one that makes you feel a lil more comfortable about the characteristic, use that one. If it does not work well enough for you, keep thinking about a new one and try that one.
Disclaimer:
Let it be said that I don't condone flirting, or turning a blind eye to any 'not necessarily harmful' trait. I am merely answering an asked question about a specific problem that has been deemed incurable, and hopefully helping someone to find a little peace in their life.

Sean