Slight chance my (39M) pregnant wife (38F) had an affair, should I ask for a paternity test or wait?

My wife (38F) and I (39M) have been together for 12 years. I don’t know how to describe it other than calling it the perfect relationship. I think in 12 years we’ve only ever gotten to the point of really raising our voices at one another maybe 2 or 3 times? We do everything together but always have never had issues…