I've known this amazing guy for about a year now. Our best friends were dating eachother. After the 4 of us hanging out a few times my friend told me that the guy was very interested in me. I was with someone at the time so nothing was made of it, but we still remained aquantinces and we always got along great. The day he found out I was single again he asked me to hang out and things just took off from there. We were together for a while, but nothing official. We've had our "title" for about a month now and I'm seeing really bad trust issues in him. He'll wrestle my phone out of my hands and go through my calls and my text messages and if he sees one from a guy he'll ask me if he can say something to him. When I get upset about it he plays it off as a joke and will stop for a few days, but it always picks back up. I can sort of understand where this behavior comes from because he had been cheated on several times by a girl he dated for 3 years and I, myself have a history of cheating.
A few days I began getting rude messages from his ex girlfriend (the one who cheated on him who now, currently has a serious boyfriend) and one of her friends who tell me that I'm too young and immature for him and that if his ex wanted to she could have him back in a second. He tells me that its not true and not to worry and that he loves me, but refuses to stick up for me at all to the ex.
Should I be worried about his trust issues? Or his ex girlfriend?