When someone is watching you, you stand taller, you try harder, you want to look good. It does not matter what you are doing or who is watching. However depending on who is watching you may add a little pizazz.
I lift weights religiously at home in the basement. Free weights and gravity only. When I am down there by myself I work hard, but there is no sparkle, I have to admit. My sons, 1.5 years old and 7 years old sometimes watch and mimic me with their own weights. But I'm not going to risk pulling a muscle for them.
But when my wife comes down there to get something while I am doing pull-ups, dips, shoulder press or squats you know it's on. My form is at it's best, my reps are slow and controlled, and I try not to let my face show that I am working too hard. I'll throw on some extra weight or do some extra reps too if she is looking. The rest is herstory.
If you don't feel compelled to show off for your lady then do it anyways, any chance you get. Why? Because it is fun, you will probably out do yourself, and she will like it. Showing off is an important part of maintaining your relationship. Feats of physical, mental or artistic prowess are a strong signal to your lady that you still care what she thinks about you.
When you take that 30 second rest between reps grab your phone and share this everywhere and sign up for one 30 second post per week to remind you to be the best husband in the gym.