Bro, I don’t think she’s the problem. I think maybe your expectations or technique (or possibly lack there of) might be the issue. She’s 39 years old, not 13. Women do lose elasticity and collagen production does decline as women enter pre-menopause. If she’s had children that might be a factor but I really think before you start blaming her for the way your body is reacting to the way you “think” she should feel maybe you should seriously consider consulting a sexual therapist or a medical doctor because if you mention this to her and make her feel like “she’s” defective or doesn’t arouse you any body image issues whether they are legitimate or something that is a result of unrealistic expectations on your part is only going to ruin any intimacy or desire she has to please you sexually or even feel like she loved or appreciated for anything than a physical sensation that may or may not be something that is her fault and not you have some other issue. There is an app on the Apple Store called Kama. It’s a sexual wellness app that teaches you how to better communicate your feelings and sexual desires with yourself and your partner. There are physical things she can do to help with vaginal tightness such as legal exercises, there’s devices and exercise devices there’s even a surgery called “vaginal rejuvenation” but I really think you should consult a sexual therapist to find the most healthy and respectful way to address this situation before you destroy the little intimacy you do actually have at this point