Just get him fixed. I don't mean to be mean, but just thinking your dog is beautiful isn't a reason to breed him. There is SOOOO much more to it, and you just risk adding to the already huge shelter dog population.
First of all, get all your health testing done to be sure she is clear of any genetic defects that would be passed on. Then find a male who has tested the same.
Second, for such a large breed wait until she is at least three before breeding her. Giant breeds take longer to mature than others.