Falling for my the wrong guy

So recently I found out that my best friend has had feelings for me for a few months and I started to see him differently now that I know that. We talk every day and I’m starting to have major feelings for this guy and he makes me super happy.

This situation may seem fine, but the issue is my best friend also happens to be my best friends ex of 3 years 😬I never anticipated this and I don’t know what to do!! help!!!