is my boyfriend in love with his ex? really long story, PLEASE help!?

my boyfriend and i have been together for 7 months as of today, actually, but i keep getting this weird feeling and i want a second opinion.

since the beginning of our relationship, his ex, we'll call her Iris, has caused us problems. when we first got together, i jokingly asked to put our relationship on facebook, making the joke that it's not official till it's on facebook, he was fine with this except he asked me to wait so he could write her and tell her that he found someone new. (btw, they were together for three years, and they had been broken up for three months, but had been seperated a few times before.) i asked why it should matter, and he said that he felt like she wasn't over him and he didn't want to mean. i didn't understand why he cared, but i guess they ended on good terms so i let it be. now over the months, we went through our own phases and ended up having an on and off relationship (that's not the issue please don't coment anything about this.) and i noticed that whenever we were together on facebook, she was no where to be found, just a friend in the background. however, whenever we weren't together on facebook, she was all over his wall. liking his posts, writing comments etc. i know that she inboxed him a few times, and the only reason i know is because i saw her name in his messages accidently from over his shoulder once and he panicked, closed the window and said "oh yeah, by the way, she wrote me asking if i still had her baseball mitt." to make it even better, a few weeks later, we were talking about it in passing and he said "oh yeah i have some things to bring to her but i know that she's never home these days, she told me she's always at her friends house." so i know that they spoke afterwards, although I have no idea what is said. she's a very sensitive subject for him and whenever she's mentioned i do get very uneasy because from the get-go i was told she wasn't over him, so i don't really like her. i asked him to take her off his facebook because i was getting sick of seeing her comments all over his stuff, and i found out that he wrote her happy birthday without me knowing. i know it's sounds psychopathic, it's just a happy birthday, but with everything she's caused us and we got into many fights because of her, i don't understand why he still needs her so bad in his life. i begged him to take her off his facebook because i feel really uncomfortable with her there, and they barely speak according to him so i don't see why she needs to be there, and he refused, he yelled at me, almost broke up with me, and said that he still cares about her, she did nothing wrong and he's not going to delete her. he asked me to get rid of one of my friends because (i'm friends with a lot of guys) this guy was making him uncomfortable, and at first i fought and said no, but then i made a deal. i realised that we shouldn't keep other people in our life if they make our significant other unhappy, so i got rid of the guy and now he still refuses to take her off his facebook. he said to me "i still have her number, i know where she lives, i can find her if i need to so why should i delete her off facebook?" and i thought that was really mean. he says he loves me and wants to marry me one day, he says he's never felt like this before, but for me he can't even take an ex off facebook... i'm just really worried, i feel like she's the one that got away for him, and he still loves her. i'm worried i'll lose him if she ever tries to come back. do you think my boyfriend is still in love with his ex???