I do believe Frodo could've had some bursts of happiness too... it wasn't always negativity...even though it certainly seems like it most of the time. The Ring gave much psychological damage, yes...(as did the whole Quest in general) but there were also happy things to think about like Sam's marriage, perhaps the popularity his cousins achieved...
and I feel like Frodo would've helped Sam go through certain gloomy feelings about the Quest too.~
That's another reason why i like this story... i like how Frodo is caring for Sam too... and i think that's important as well to portray because to me, i think Sam needed healing as well and Frodo is one who understands him best.