It doesn't sound like you have any good grounds to worry.
I think it's actually a pretty good trait for guys to have a decent amount of female friends; it means that they don't subscribe to the toxic (and prevalent) idea that men and women can't ever be friends because men just want to bone. It means they see women as sentient and complex human beings, not just sex objects - the fact that you say he's 'not super laddy' would seem to support this interpretation. Unless you have reason to believe that he's f**king all his female friends - and it doesn't sound like you have any evidence - I don't see any issue here.
However, this insidious view - that men only ever want sex from women, and therefore if they're friends with them, it's just a means to an end - is really pervasive in our culture (see 'friendzone', for example). It's based on a load of unhelpful, essentialist gender stereotypes, and in short, it's bulls4hit. I can understand why you feel insecure though, because this interpretation fits very well with our received ideas about men and women.
Yes, loads and loads of men are awful, and some of them exploit female friendships in order to get into their pants. However, this isn't something that's hard-wired into the male lizard brain though. Some men - straight men - genuinely do get on better and relate better to women, and have long-term, close, intimate friendships with them. In the absence of any indication that something untoward is going on, this sounds like a likely explanation. If you have a boyfriend who's able to have healthy, non-sexual, equitable friendships with women, that's A Good Thing, in my opinion.
Maybe he is a philanderer and a liar and he's shagging 5 of his female friends at once. This is something you need to talk about together though; you need to bring up your insecurities with him, because at this point, that's all they are - your own insecurities.
If, as I suspect will happen, you get no indication that he's cheated/ing on you with any of them, you're going to either have to get over it or break up with him if you can't handle it. It's really not a good look when people try and police their partners' relationships with friends.