Not sure if he's still into me?

Me & a guy from work have been having a thing since Oct. 2011. We are both married (plz dont judge, I know) but both marriages are loveless. I said NSa from the start, but he fell hard & fast. Then one day like a light switch he pulled back. Stopped texting, stopped flirting, talked with everyone else but me! Yet still wanted to continue the NSA. We've had a fair share of drama this whole time as well, like territorial jealousy on both sides. Basically he had feelings first, then turned them off when I caught them. I pissed him off cuz I told this other girl that was coming on hard that we already had something going on. I knew he'd b angry, he stopped speaking to me for months. I left work for over a month for family emergency in early 2013. When I came back, he started speaking to me again & flirting, etc. i remember him telling me he wanted me to show attention, and i did. Normally im very discreet & dont like everyone to know my business. So, we all went out to the bar a couple months ago, and he was flirting & hanging w a coworker, but kept staring at me thru the night. She left, and he acted like I wasn't there, so I left. The next week, he's telling me he was upset I left and asking why! For the last few weeks, he's been pretty much ignoring me, but then one day he will drop a compliment or flirt then walk away. It hasn't been just sex with us, the feelings are still there, I can tell when he looks at me, or when he pointedly talks to everyone but me, etc. I just don't understand what the deal is anymore. Are his feelings in the way? Is he intimidated? Or is he just not interested in me anymore...?