He'd rather be single and pull girls? Than have a loyal girlfriend?

So I've been with my boyfriend almost two months now.
Everything's been perfect, barley argued, always out doing things, going out! spending time together.. And his family and my family get on etc..
No faults to this relationship.
But, 3 days ago.. He said "I'm feeling unhappy, l will have to tell you in person. I can't text this but I've been unhappy for a week or two now "
So I met him, he voiced his opinion on what his boys have noticed.
Apparently his friends have noticed he's "changed" and he's not himself recently, so he now is debating on ending us..  Bare in mind all his mates are single.. 
Yesterday he told me "I'm fine. Just need a few days to get my head straight. We both care about eachother so we will get through this, it's just a rough patch."
Today.. 
He told me "I can't have fun anymore like I used to when I was single, I can't go out with the boys, get drunk, pull girls and have a laugh about it the next day"...
I don't know what to do, please let me know your opinions on this..
If it's ever happened to you?
Because I truly care about him and I am so so happy.
I know if this ends I'll just be searching for another him in everyone.😞