My wife and I moved up to St Ives last July with our 9 month old son. I work full time in Cambridge (off Madingley Road) and my wife works from home two days a week (but occasionally has to travel for the day - London, or other cities). St Ives is nice, and I'd say there aren't any dodgy areas!
However, I'd question your husband's commute to Cambridge. It depends on where he'll be working, but it can be a right pain at the moment. I cycle 2-3 times a week now the weather is clement, and drive the rest. Cycling takes ~60 minutes plus a shower (each way), and driving is normally 50 minutes of sitting in traffic (maybe a bit less in the afternoon). It's painfully slow to get out of St Ives because there's a single road everybody has to take to get to the A14 due to the river, the A14 is slow because it's always slow and because there are roadworks for the next 3 years, and getting into Cambridge is slow because it's old and not built for cars. The bus is OK, depending on where in Cambridge you're going. If you want to go at rush hour, then as soon as the bus leaves the guided busway, it's just in regular traffic and not very fast.
We're currently looking for a house somewhere closer to Cambridge. We'd love to live in Cambridge, but the houses are either too expensive or in... let's say 'not well reviewed' areas. Cambourne is enough closer that I could cycle most days, and have a lot less traffic to worry about (although still a fair bit). There are also lots of villages that are closer, but most of them are too small to have much in them - the most any have is a few shops and a pub - so you'd need to drive a lot just for day-to-day chores.
Don't mean to be a downer! St Ives really is really rather nice, and we've found lots going on (over time) for our now 1.5 year old. I just don't want your husband to get as riled at the commute as I do. It doesn't help that my previous commute was a 15 minute walk through a park...