now:has a rule in company/intertainment to have a girlfriend?

Er.. are anda asking if they're allowed to have a girlfriend? Because I've heard of a company placing a dating ban on a group, but idols have been known to tanggal secretly to try and avoid scandal. Like Jonghyun and that actress chick, SM denied they were dating at first but eventually they had to konfirmasi it and a big skandal happened.. and now Baekhyun and Taeyon.. but as far as I know, technically they're free to tanggal whoever they choose, though no one in SHINee appears to have a girlfriend as of today.
I don't know if that made sense atau if that was your question, but hope it helped some.