Depends how old you are and how susceptible to trends and peer pressure your man is. Did he get the Bieber cut last year? Did he read Game of Thrones this year? Does he have a nasty habit of parroting his friend's moves and ways? Some young men stand on their own two feet, others look to their friends to find out where to step. Hopefully your man wears his own shoes.
Yes, the Domino Effect can be real in friend groups, but when it comes to some sort of mass dumping of GFs, most crews fall short of that. Unless your relationship is already on shaky ground, and unless his buddies are texting him every 45 seconds with some "OMG, dude, me and J havin the friggin time of our lives. Bein single rocks :) Hurry up yo!," all will be fine.
Your man should be able to handle the shifts in his friend's lives without making changes himself. Adults do it all the time. And frankly, if he can't, screw him. Do you really want the glue that keeps you guys together to be his pal's relationship status?
Funny Guy
Really, though, if you guys are adults, it's not simply going to dump you because his friends are now single! Even teen boys wouldn't always be so prone to do so either. Indeed, a teen, after his friends gotten over the initial pain of heartbreak, would probably rub it in their friends' faces he's got a girl.
Thats the hardest part of having relationships is the influence of his guys friends. I agree if he is an adult he will have the backbone to know his own decisions and not be influenced by his other friends. and if he is influenced by his friends to be single and not in a relationship then he is immature for you since he cant make his own decision and has to rely on other people. my ex did the same thing his friends did a mass dumping of gf just to party at wazzu and he dumped me to be with his friends. do you really want someone like that. so just ask him every once in a while look hey are we okay and get that communication out there just for him to know and you to know whats going on.