This can depend on the specific individual and situation, but for the most part Leo men will get competitive when jealous. This becomes their knee-jerk reaction because they’re too prideful to outrightly display jealousy but still feel the need to dominate. By acting competitive, a Leo man can prove his superiority and ability to stand up to threats.
Remember that Leo men are the type to put the people and things that they love up on a pedestal. They’re loyal to a fault and become possessive when they feel threatened to lose something they love. So when you see this protective nature come out, it’s very likely that your Leo is feeling jealous.