There's no trust in my relationship

So my boyfriend and I have been together for a year. In the beginning of our relationship everything was great. It takes me a while to build trust in people because of previous relationships but we worked things out. I always told him that trust for me takes time. About 5 months into our relationship we were both looking at his phone while he was Googling something (I wasn't snooping) and I saw he Google's his ex girlfriends tumblr. I was pretty upset but we talked about everything and he told me he was sorry and I forgave him. But I got suspicious so I looked through his phone the next week when he wasn't paying attention. I saw on Facebook he had messaged a girl asking how she was doing. (Which wasn't THAT bad) but I started reading the previous messages that were from before we were together and he was begging to go out with her. So I again we fought and I forgave him. Recently I saw him commenting on a girls picture saying she was pretty. And I just feel like after all of the mistrust and after all he complains about my jealousy, he makes things worse. I don't know if this is all in my head or if I have reasons not to trust him. He deleted his Facebook but I feel like that isn't the root of the problem. Idk what to do! I feel like I keep forgiving him like an idiot. When do I say enough is enough? He says it isn't cheating but I'm still hurt.

Wow!! Did I write this? I have been going through the same thing for the past 3 years. After a big blow up today, I have been searching online all night trying to figure out answers to if I am wrong in my feelings of being jealous. I know he isn't cheating but I don't like finding on fb that he is telling another woman how attractive she is and I don't like seeing him call other women terms of endearment names such as Doll, Dear.... This has been our only problem besides drinking and that is when most of those comments to other women are made. After so many arguments over it, as wrong as it might be, I decided to play back to prove my point and show him how it feels since explaining my feelings never worked. I made a very innocent comment on a mutual guy friends picture on fb. Immature for a 50 year old? Yes, it is, enough was enough. He didn't like it. He said it was flirting and made him jealous and uncomfortable. Imagine that. I will see if it made an impact on him. I don't know if that is the right thing for you to do and really wasn't trying to offer advice since I am looking for it myself. I was looking for opinions from others on your post. Hope your bf wakes up and realizes that is does hurt. I hope mine does too.

I'm responding to you and "New Realization". NO, you are not just jealous! NO, it is not in your head and YES, what these "boyfriends" are doing is a form of cheating. What the hell is the point of having a partner if they're willing to hurt you. When you are in a committed relationship, you don't call, text, email or indicate in any way that you are open to "something". That is what both of your boyfriends' are doing and their bullshit line of "your just jealous" has been used to shut women up for too long now. It is not jealousy to expect your partner to be loyal to you and to honour your relationship.