HELP!!! Need advice ASAP! (Work related)

Okay ladies, I need some help because I am at a loss and I don't know who to turn to for help. I am a waitress at a local restaurant in a small town. I have a customer who is an older guy and he always comes in to see me. At first he was just like any other regular except he only came in for a glass of a water while he sat and drank his coffee from the gas station next door (it's also a truck stop) anyways, lately he started specifically coming to see me and then he started holding and kissing the back of my hand and then he was hugging me and then kissing my neck and the other day he even tried to kiss me on the lips! He's invited me to have breakfast with him outside his work and at one pointI sat in his truck one day after work just to sit talk. I thought he was just being a sweet old guy but now things are getting way out of hand! One of my coworkers apparently started a rumor I was having sex with him and when I told my bf about it he accused me of hiding things from him and was worried I might get raped (he's a rape victim himself and I guess my story triggered something). I want to tell this guy to back off but I also don't want to hurt his feelings, I don't think he means any harm but it's getting weird and I know he'll be there when I start my shift tomorrow. Please help.

Also, in a related story I have a coworker, who is a chef and brother of the restaurant owner. I've always liked him because he made sure I ate and is one of the nicer people I work with (there are some not so nice) recently he had a talk with me about the rumors my coworkers started saying it really upset him that they also tend to treat me unfairly (like I said, some not so nice) and so I thought that was sweet and was glad to have an ally. But we've started chatting on Facebook and he keeps calling me beautiful and says he'll miss me since we won't see each other at for a week (we are going out of town at different times) and I know he also means no harm and I had started to see him as a father figure of sorts but now I'm concerned considering the other situation I'm in. I've never dealt with this kind of stuff before and I feel like I need to set some boundaries without being to harsh but I'm not sure how to go about doing that. (Also with my rude coworkers, I don't wanna start more drama but people keep telling me I need to stand up for myself) Every bit of advice helps.

Update: my boss talked to the older man and apparently I'm not the first waitress he's done this to, he says he forgot to warn me sooner and hopefully it will no longer be an issue. But thanks again to everyone who responded, I was prepared to talk to him myself but glad I didn't have to today.