What about Matt 18:15-17? If someone sins against you tell them once privately, tell them again publicly, and if they still won't listen, "treat them as you would a tax collector". And the "forgive them 70x7" thing is talking about someone who keeps wronging you and repenting.
God's forgiveness of us isn't unconditional either, it is dependent on us recognising that we have sinned and asking his forgiveness through Jesus, isn't it? I know we don't have to list every thing we've done wrong every time but the general principle is that we repent and believe and are forgiven.
This is a great article on the subject - John Piper (scroll down a bit)
He says "the difference is that when a person who wronged us does not repent ..., he cuts off the full work of forgiveness. We can still lay down our ill will; we can hand over our anger to God; we can seek to do him good; but we cannot carry through reconciliation or intimacy. "
OP sometimes I think it might actually be wrong to forgive (in the sense of acting like there is no problem and allowing them to carry on doing it to you!). The person who is hurting you needs to understand that they're doing wrong, and if you let them off and keep acting like everything is ok, they're never going to get there - until they meet their maker and He tells them, of course. The bible is very clear that we are supposed to 'rebuke sinners', we are supposed to tell people if they hurt us.
If the other person is unrepentant and and you are not allowing yourself to get angry at what they are doing, if you are downplaying what they do, then there is a big chance that you're not actually 'forgiving', you're simply 'forgetting', 'overlooking' or 'pretending they didn?t do anything so very bad'. I think that acknowledging the need for forgiveness is an integral part of it.