While it is important to be able to tell the difference between people being imperfect in the way that all humans are imperfect and people being imperfect in ways that make them Not Right For You, I don't think all divorces can be predicted from the outset. As time moves on, people do change. Nothing is guaranteed. Committing more does mean there is a risk of a "much harder crash further down the road". You just have to decide if the rewards are worth the risk.