Could reccomend a handful of supplements to take bu that won’t solve the issue. You’re better off talkin to he about this and seeing if there’ve anything you can do to help ease her stress levels. Maybe cook dinner a few nights a week, play with the kids while she takes a nap, or even a back rub once in while will help. Odds are are unless she is in her late 40’s that it’s stress or self image related.
Even if none of the above do not push her or attempt to seduce her when she clearly isn’t in mood. That will only make her push back further. Instead try to remember something she said she wanted done and go do it. Then when it’s done don’t expect/ask for any reward. She will have to think of a way to thank you. Hey it works for the Swedes.