That's what speed 3 or 4 is for. Slap that on and it's usually over in pretty much no time at all.
Besides, I can use my second monitor to watch video's while playing Sims 3 full-screen. I just have to pause, alt+tab to the monitor to select a new video when it's done, and then go back to the game.
That works absolutely fine.
Also, to answer the question, no there isn't a way to fix it. You either have to have 2 monitors of the same resolution and stretch the game across both (a lot of people with high-end rigs use 3 monitor setups in this manner), or run the game in a window, without it filling the screen like your screenshot shows... or run it full-screen.
When playing on my desktop, I use my primary monitor at 1920x1080 and the secondary at 1600x900 and either use it to look up tips (which requires pausing and then alt+tab), or watching netflix.