Male dog fear agression update

well since sammy been a puppy to now 2 and a half nearly and has been attacked by offlead dogs over 10 times, it seems the poor mite has male dog fear agression, i know when he's going to react and change direction and try to calm him down, we have a female Dogue De Bordeuax rescue at the mo who we are adopting. he loves playing with them and gets on great with all females no problems what so ever, but when out and he see's a male he reacts fearfully, it's so so sad to see him go all fearfull and upsets me, ive come to the conclusion he has to be on the lead and try and not see male dogs, i know by his body language if he has a surge of fear we change direction, luckily for him ive found a old famers field who lets you have dogs offlead, so he can go and play on his own or if any of my friends with females, he doesnt snarl or bare teeth ect, he simply barks loudly and deeply and goes on his back legs, but by god to see him it's horrible, i always keep calm and reassure him if we do see males. it was to update to all who offered me help last year ect mainly smokeybear, hopefully we can work on it and eventually he wont see males as a threat.