Thyroid issues are a huge problem for premenopausal and menopausal women, causing not only weight gain but depression. Get her on the correct med regimen, walk with her on a daily basis, or at least set some regular physical activity that you both do together, (sex and foreplay are great for this) and work on rekindling the fire that both of you once had for each other. Do this slowly and regularly. Don't tell her what you're doing, just do it. Praise her , flirt, tease, just like you did when you met. You will find that she will not only be interested in sex, but will become more interested in how she looks, her weight, and her fitness. You both will be more sexually active than you've been in years. If you are like me, you don't want to divorce and cheating is out of the realm of your comfort level. Sooo, she is the only game in town. Nurture this, train her and condition her to crave you, and you will also desire her. Nice combination...