I have been dating a guy for the past year and a half but to give a background, he liked me for 3 years before we started dating. We had tried once before but I was not into him and had broken it off. We took a break for about 6 months and in that time he tried to see other girls, one in particular named Bailey. Now, reverting back to the current situation, she visited for the past week since she moved to another state and he, a couple, and her hung out altogether and alone the entire time. (I was so busy with work that I couldn't be involved.) Now, he claims they are just friends but a few signals and actions made me jealous

1. She was drawing/fake tattooing all over his body and getting way too close for comfort and he defended the situation
2. Whenever he would try to do something for attention, he always would look at her immediately, even if I were in the room
3. Would always try to spend time with her
4. He would claim to be tired and want to go to bed and then when he would see her, say online, and would tell me never mind, but not say it was because of her but another reason (which I found out that it WAS her he was eager for)

Now, I am dealing with jealousy issues, obviously, and I know that in my head I have no reason to be jealous since he has liked me for so long, but I still feel in my heart that she has something either that I don't have or just he is attracted to her more. Am I going insane, or should I really be worried? And if I am really just going insane, is there any steps I can do to become for secure in myself and this relationship, because really.. I want this to work, but it feels helpless.

Lastly, if there is a problem, and I am taking a 4 day trip with him this weekend, is there any way I can bring up the conversation without him shutting down?