[comm]

For a guy to stick to 1 woman sexually and vice versa, it definately needs emotions as a glue and also sufficent physical attraction

Each persons defination of sufficently attractive is different

Wadever it is, the physical body part of the equation can be address via exercise or even plastic surgery but i feel its unreasonable to expect the wife to do all this, unless of course the husband does it too so both can enjoy increased physical satisfaction with each others body.