You really don’t need to run a background check on the guy you’re going out with, and so what if you don’t have mutual friends who might help you. When you have lack of contacts, use his. How? Hang out with his friends. You’ll read him like an open book. Remember what they taught you in grammar class about birds of a feather flocking together. So here’s what you learn from the company he keeps or from the way his company keeps him:
The way they treat you: If his friends show you no respect, make you feel uncomfortable, treat you like a pile on or flirt, and make passes at you, then he obviously does not care enough for you. You know the way out. But if they seem to know a lot about you even though you just met them, if they constantly reinforce how great your guy is, and go out of their way to be nice to you, that means he talks to them about you and they know you’re special. This guy is worth holding on too. 

The way they dress and behave: Every guy thinks he’s really cool and in his mind, so are his friends. And boys love to tell stories about all the fun things they do together. So he might paint a picture about his friends being as hip as Archie and the gang, and chances are that is true. You will probably end up meeting Archie and the gang just as they were… in the “60s” and realize that man is quite the nerd. Now you have got to get your priorities right here. If this supposedly “uncoil” setting embarrasses you’ it’s your call. You can show yourself out. But if you’re in it for him-drab nerd appearance and not so hip friend’s et al, you’ll have to work yourself carefully around this. Go out on your own more often. Explain that you are uncomfortable around his friends (you can keep the “they’re so uncoil” reason to yourself). 

The way he treats them: If he regularly bitches about his friends, or if he’s constantly lying to them about where he is, and what he’s doing, there’s obviously not much love there. And if he is always shooting his mouth off about the people he claims to be closest to, well, who knows what he’s saying about you. But if he treats them with respect, trusts them and is there for them whenever they need him, it says a lot about the kind of man he is. 

The way they feel about themselves: If his friends lead an extremely lavish lifestyle that you find ostentatious and suffocating, if they look you up and down to see what you’re wearing, if they only interact with people of the right financial and social positions, you should know that you’ll never fit in with his crowd. But what’s important here is your man’s attitude to this. Does he agree with their we’re-better-than-everyone-else attitude? If yes, you know what to do. But if he’s not like that, and doesn’t let his attitude change because of them, encourage him to meet other like minded people. Subtly. He’ll enjoy himself and you can breathe freely and behave as uncouthly as you wish.

The way they treat him: If he’s the but of all their jokes, if he’s always footing their bills, or bailing them out of trouble even at the cost of his own reputation, then he’s probably a sucker who doesn’t mind being manipulated and used, just so he gets to hang with them. He’s a classic case of the nerd who is in awe of his friends but is only accepted by them because he has something to give. So strategies either inspires self-confidence in him the way only women can and get him to change his friends or leave before you loose all respect for him. 

The way they party: If his friends give you the creeps, have disgusting hobbies and interests such as alcoholism and drugs, regular visits to dance bars, gambling and tend to indulge in street fights or bar brawls, get in constant trouble with the law if it’s for drunken driving, you can be sure your man is no saint either. And while he may successfully cover all his flaws, he or his friends are bound to slip in conversation about their lives. So pay attention and get yourself out of this mess at the first sign of any trouble!