Love is of the spirit and mind, but lust is in the flesh.
You should lust after your wife!
Desire her with a passion even the sun would have a hard time outshining. A life-long romance requires more love than lust, but keep the physical as long as you can.
That means she has to stay in shape.
And that means she has to want to stay in shape.
And that means she has to want to stay in shape for you.
And that means you better be in shape first.
Be what you seek in others.