Relationship help, as always. What should I do?

First off, I am 18 and female. Mike is 20, Dave is 17.

I just got into a relationship with a guy, his name is Mike and he is the kindest person I have ever met. We’ve known each other for about a year but have only been dating for about 2 weeks now. He says he loves me and we get along so well and although I am terrified, I am very happy.

But here is the problem, my ex boyfriend, Dave, who I was with for 2 years and madly in love with, has now come back into my life because we want to be friends. But he wants me back and I’m just so confused.

I love Dave, I always have and always will, but this thing with Mike is probably the healthiest relationship I’ve had since Dave broke up with me over a year ago. But I’ve been waiting and hoping for Dave to want me back this entire time, why does it have to be now? Now that I’m in a relationship with a boy who treats me better than anyone?

What do I do? Do I pick the one man I’ve ever loved and probably will ever love, the one that I used to be so sure was meant for me? Or do I stay with the sweet boy who I might fall in love with and who might break my heart all over again?