I'm not sure if my imagination is running away with me here.
Relatively new man, we've been seeing each other about 6 weeks and a we're exclusive but it's early days.
A had a nagging annoyance throughout in that he seems to be online on whatsapp quite often and very late at night. We're late twenties, but even I don't get 1am or 2am texts from friends on a daily basis so it made me a bit 
wondring who the heck he is talking to all the time.
He's not weird about his phone, and he doesn't use it at all when he's with me, and have noticed he aslo doesn't really get late night texts when he's with me either. I did notice a text from one girl a couple of weeks ago, and it was just friend stuff but it came at midnight. He'd just left the phone on the table and it flashed up. Nothing funny on the text, no kisses, just a contuinance of a conversation.
I was a bit so I checked on that girl and found she lives overseas in a place he used to live, and maybe the time diferrence might be why all the late night texting. He does hve a lot of female friends. She's not especially pretty, but he "likes" a lot of her photos. More than he does mine actually.
Anyway, he booked a holiday to go over to see friends. Says he has a lot from when he used to live there and obviously this girl lives there too. I didn't ask where he was going or who he was staying with - we're not at that stage yet and would not know who the people were anyway- but we made a date for the day after he gets home.
Not heard from him much, and I have noticed a couple of things that would indicate he's with this girl. Same photos being posted from both of them, that sort of thing. Also noticed he's never online texting since he's been away.
Am I being totally paranoid? Is he likely shagging this girl or is there a good chance they are just good friends? I've no reason to find him not trustworthy but it's nagging at me.