First you need to have a healthy discussion with your wife regarding inactive /low sexual desires due to which reasons. It may be negative attitude towards sexuality /seeing it as painful /shameful /heard negative things. You can do masturbation as per your natural rhythm of sexual desires till your wife comes out by herself.
Next Steps
For proper penile erection, you need to reduce your wt gradually 2-3kg/month till 80-85 kg. You can do regular exercise and maintain healthy diet for it.
Health Tips
Kindly tell your wife to consult herself on practo for better evaluation and treatment. Happy to help. Take care. Bye!