How to help a Leo-Leo relationship work for long term?

My boyfriend and I were born on the same day(he's a year younger though) and we having amazing chemistry. But in our relationship we bicker a lot. When we're good we're fantastic but when we fight it's ugly. The pendulum definitely swings both ways drastically. Probably because we are both so stubborn and prideful. I want to know how to help make things smoother and calmer. It can be difficult because we are both in our late 20's and set in our ways. But he's my everything and I want to keep this going for a long time.