Great wife you have.
As mentioned earlier by others arose the interest in her. Both of you watch more porn go for vixen, joymii, couple types first where females are comfortable.. Slowly shift to threesome cuckold swapping gangbang orgy etc.. Then go for videos from dogfart, blacked etc.. Also go on vacations to beach sides like Thailand, goa, bali etc and make her wear bikini, then shift to things and gstring.. Of course she will get attention and you praise her for that.. She will be now more comfortable with this things.. Take things tep by step and you will success.. Once things are ok plan for see through dress, hotel Or beach dare. Fuck her in secluded private areas like hotel balcony, home terrace morning beach. Go for couple massage. Say that you like her to get temporary tattoos in private area.. In that way she will be more liberal and relaxed. Once liberal she is all yours to mould her as you wish..
Good luck and enjoy