You spell it libido. This happens to everyone at some time. And from time to time. Try to reduce stress as thats the main libido destroyer. Find time to relax and chill together outside of the bedroom and away from the interference of others doing things you both enjoy. Talk to each other and try to agree a mutual time at least once per week when youll put time aside for sex. When the 22 year old is at your house then I agree it might be awkward but they arent around all the time surely? When she goes out – get to it! You need to make the effort for your wife like she did for you. Which may sometimes involve trying new things and making love when maybe she wants it more than you do. And vice versa. Thats called putting your partners wishes before your own and it will win you brownie points in her book.
Finally your testosterone levels may be low. Get checked by your GP. If these are fine then you can still boost your sex drive naturally. Regular exercise. Good restful sleep. Zinc supplements and bananas all help. Sex is an important part of a relationship between the two of you and shoyld not be neglected or it may cause issues generally in your life together. Good luck. Let us know how you get on. Hope Ive helped