You can use paypal on a 'love' dating site but not an 'adult' dating site as paypal do not allow adult content. Google ccbill and zombaio if you want credit card processing. Best option is to get a merchant account, or several merchant accounts and spread the processing. But merchant accounts are not easy to get these days, you need a good trading history.
Don't be fooled by all the companies offering to set you up with a merchant account, loads will allow you to build up a nice wedge of money then freeze the account with some story of bank investigation. You will never see the money again. Best bet is deal direct with a bank and use a credit card gateway company like netbilling.