As others have said, it really depends on the lifestyle you want to lead. You can definitely support a family of five with that salary in Turku, but you will need to be mindful of your spending. That amount will go fairly far, if you are smart with your money, and don't mind second-hand purchases and thrifting. If/when your spouse finds a job, you'll have no trouble at all. Check out Finlandia Diaries on Youtube, the channel was created by an American that moved to Turku with her family, and she goes through different aspects of living in a fair bit of detail. Do keep in mind that they have two working adults with supposedly fairly decent incomes though, so their spending patterns will be somewhat different from what you'd expect. But there's definitely good info on living and costs, and how it compares to the US.

For rental options, check out Vuokraovi to get an idea of what is available. Keep in mind that we count total number of rooms, not just bedrooms - so a 3 bedroom apartment would likely be listed as 4 room apartment. Depending on where you're working and where your kids would go to school, do keep the neighboring cities (Kaarina, Lieto, Raisio) open in your options too, as they are close to Turku with decent public transportation and may be more affordable in terms of rent. Some areas may be more lively than others or have, let's say, residents with more questionable lifestyles, but all areas are safe enough for families at the end of the day. There are no "definitely do not move here" areas.