Boyfriend (41) keeps adding female friends on facebook

I'm 30 and my boyfriend's 41 (supposedly old enough to be mature).

What brings me here is not knowing if I'm right or if I'm being insanely paranoid and jealous - which I must admit I am a bit, even if I try not to show it - so here goes:

When I met my boyfriend, he was still married and had like over 1000 friends on facebook, including LOTS of random/slutty girls and would leave provocative comments on their pics (ego boost, I find it so sad in a grown up man). He was always flirting with these girls for everyone to see (comments page), I remember thinking "this guy's a womaniser" but didn't think much about it - he was only someone I knew. Meanwhile, he got divorced and we got closer - we fell in love and he made me the center of his world, but this kind of behaviour was always in the back of my mind: I always fear he'll go back to his old ways once I stop being "new" to him (we've been together 1 year three months). Ok, maybe he once did that because he was unsatisfied, maybe he's not like that anymore, or maybe people never change, or maybe I'm just being plain paranoid.

Without me having to ask for it, he then gave me his e-mail password (which then changed cause I asked him too, I don't think I should have his password) and he started deleting facebook friends until he was left with a little over 150 friends, which I knew were friends and family. For a year it remained like this, but lately he's beed adding a lot of people, like 20 a day - some of them had been on this facebook before, he deleted them now is adding again. He's adding most of them, because the requests are accepted when he's not online, so I know it was him who made the request. It seems to me that he knows the women he's adding, because I see they're friends in common with his brother, with other friends and most of them are from his home town - some are from where we live now, I don't know who they are, but from past comments he left on their profiles before he deleted them I can see they're familiar to him (note: normal comments, non provocative ones - since we're together I never saw something that would seem unapropriate). Some are fat and ugly, other are beautiful...he also adds men, but my paranoid side (?) thinks he's going back to his old ways and that the fact that some are men and some are ugly old women are just a way to make any possible dirty intention remain unoticed, to make everything seem inocent and normal. At the same time, I don't think he'd put that much thought into it, I don't think he'd be so manipulative to this point at all.

I realise how stupid this sounds, this is just facebook and it's all about trust issues and ghosts from the past...I don't believe in controling anyone - whatever will be, will be - but last week I confronted him and asked why he's adding all this people (including women) when he'd made the choice to detelte them before, asked why was he doing that and insinuated he was going back to his old ways. He said his old ways were dead and kind of laughed of what I said (but he'd go nuts if he was on my shoes), he said they were all friends or people he knew and cared about, and just wanted to have them in his contact list (which keeps growing like 10 new adds/day).

So, the fact that he keeps doing this even after I said it bothered me could mean one of two things: he's innocent and hasn't put much thought into it or he just doesn't care about me. However, he's always so attentive, so caring, sends me e-mails with songs almost every day, calls me whenever possible...that almost makes me feel stupid for being jealous, but I am. He hasn't been faithful in the past with his ex-wife and although I know I must live in the present, it's not easy to let go of what I know. Am I being paranoid, or once a cheater, always a cheater? How should I deal with this?

Your insights on this please?