When I have been *truly* in love, I've had no desire to look at other woman. But, even if the relationship lasts that level or type of love doesn't usually. It matures, changes into something different but not necessary better or worse.
Anyway, she has a right to be upset. What they need to do is talk and set ground rules for that kind of stuff. Something our friend SB knows a lot about. But they probably won't. He'll go on watching porn and drinking beer and she'll go on yelling at him.
And the short answer to your question is yes, a hot ass is worth it.