My wife has little interest in foreplay but I can’t get aroused without it

Your final question really needs to be addressed directly to your wife. Through discussion and experimentation, it will be necessary to find alternative, palatable methods of increasing your level of arousal. I wonder why she did not reveal her revulsion about penile fluid at some earlier point in your 20 years together? Perhaps she was ashamed about it, but it may be a genuine phobia, which would require treatment. Most men do need more direct genital stimulation as they age, and their partners often need to be educated about this, and reassured that the reason is nothing to do with them. Unfortunately, many partners of middle-aged men start believing they are no longer sufficiently attractive to inspire an instant erection. Not understanding that a man’s body only works that way in his youth, they have unrealistic expectations and, as a result, sometimes suffer from a loss of confidence that can lead to withdrawal from sex. Some couples’ style of foreplay is mutual self-pleasuring, which may be an option in your case. There is also a variety of toys that would be worth exploring together. Either way, it is imperative that, as partners, finding the way forward becomes a fully cooperative venture.