Search Results: making girlfriend jealous

All of you guys make good points on both sides of the issue, however my situation is a little bit unique. My girlfriend and I broke up for about a week about a couple of months ago and during that separation she spent a few nights with this other guy that used to be mutual friends with the both of us. The first time they hung out we were together, but arguing so she went for a walk, ended up at his place which I had no idea where it was, for 5 plus hours... Said she was just having a beer with him, that nothing happened between them however she did happen to mention that she was crushing on him after the fact. The next time we were fighting and she left, ended up staying a night or two at his place, and when I asked him if she was there he said no so I pushed my way into his house and found her, at this point she said she just slept on the couch. Fast forward to present day, she and I are back together and living with one another again however she remains FB friends with him, likes a lot of his posts/statuses, likes a few of his selfies, and often texts him whilst at the same time virtually ignoring my FB entirely even when I write her or post stuff. Some specific posts involving him that she liked are "Stay well lubricated sleep with a mechanic" (btw he is a mechanic), as well as liked a post that said " I'm a mechanic. The person your girl calls when you can't bust a nut" (A little background info: A while back I took a bunch of Cialis while drunk off my ass to try it out cause my stepfather gave it to me and I was curious... Long story short I couldn't get it up till morning... lol embarrassing). Anyway, what is your view on this? Am I wrong for being jealous about her remaining FB friends and making these sorts of comments? Is there something going on between them? P. S. she also only follows about 7 people, one of which is him, and none of which are me.