This is a true story My girlfriend and I have been together for a little over a year. She is 5'4" with redish brown shoulder length hair. She has light skin with beautiful blue eyes. D cup breasts. She is 29. We go to the gym almost every morning together so even though she has a slightly thick build she's in shape. Her legs and ass are athletic from weight training. At her job she works with low income people on a case bye case bases to see if they qualify for food stamps. She has always wanted to help people and is one of the nicest people I have ever met. Our sex life is amazing. She's willing to do almost anything. One day as we were getting ready for work I noticed she put on a dress but no panties. I asked her why and she said "why not?". I told her it turned me on but odd she was wearing it to work. She told me she was glad it turned me on. Anyway, I decided to go to her office and surprise her that day hoping we could take advantage of her no panties. Several people work at her office but there is a back room for their client meetings. Her co-workers told me she had just gone into that room with a client. So I went back to see her. The room was closed and the one window had shades drawn down. Now I was worried. I tried the door handle but it was locked. Long story short but after a few minutes I was watching and listening from an air vent in the ceiling. She was sitting across the desk from a bigger black man. He looked to be in his 40's and from a rough life. He was talking about how stressed he was from all the shit going on in his life. His ex-wife and kids and losing his job. She was talking about what other jobs he was applying for and what seemed like normal stuff. Then he made a comment about needing to release some stress and needed to get some ass. I thought my girlfriend would make a comment about that not being appropriate but she shocked me bye saying how sex helps relieve stress and is healthy. He then responded with "How about I fuck you?". She stood up and walked around the desk. "If that's what you need" she said as she walked. He turned his chair to face her. She got down on her knees in front of him and started undoing his pants. I couldn't believe it. I was in shock and just kept watching. She pulled out his cock which looked very large. Bigger than mine. She started giving him head. He had her hair pulled back and was holding onto it. I could hear her gag every now and then. She would go down and suck on his balls, lick up his shaft and I could see all the saliva she left on his cock. After a while he pulled up on her hair and she got up straddled him. I saw her reach back and put his cock in her as she lowered herself down. Once it was in they started slow and she leaned forward and was kissing him deeply. Holding his head in her hands while his was on her ass. I could see them using tongues. She started riding him fast and hard. After a while he lifted her off him. He stood up turned her around and bent her over the desk. He lifted her dress and smacked her ass hard a couple of times. She let out a few yelps of pain but seemed to wiggle her ass like she enjoyed it. He said "are you ok with that?" "I want you to do whatever you want with me," she replied. With that he smacked her ass a few more times then shoved his cock back into her. He fucked her hard. I could see her ass cheeks rippling as he pounded her. He pulled her hair back for a while. After a bit I could tell he was ready to cum. He grunted and grabbed her hips pulling himself deeper and came inside her. I know she's on birth control but STD's came to my mind immediately. Although maybe for work stuff she has seen his records. After he was done and pulled out she turned around and dropped to her knees and cleaned him off with her mouth. "Feel better?" She asked. "Fuck yea," he replied. They gathered themselves and talked more about his job search. He asked her if they do home visits. She said no but if he wanted she could take an afternoon to go to his house discuss work and evaluate his situation for the case. He told her next week the kids were at their moms and she should come over. She said she would see what she could do and let him know. After he left I went to her office but pretended I had just arrived and was waiting for her. I didn't tell her anything because I was in shock. I haven't said anything about it yet, not sure why I can't. But this Thursday is the day she would be meeting him again. I guess I'm waiting to see if she says anything and waiting to see what happens.