Ex boyfriend coincidence

Hi, I'm a believer in fate and coincidences, but this one has threw me off...
I'm currently not over my last ex boyfriend (we've been broken up for about 1 year, we were dating in 2009) and we haven't spoke to eachother at all but I still think about him a lot and miss him so much.

I've just started university and was so shocked to find out that my previous ex boyfriend (from about 4 years ago dating in 2006/2007) is on the same course as me. I had no idea about this and I think I might have avoided going there if I had known because I thought I'd got over him and he went fat, grew his hair long which isn't my type, just let go generally. And I started the course and he was there, and even though i've left halls it happens we were both staying in the same halls (despite both living in the same city as the university and nearby areas). Anyway I went to the course on the first day and he said Hi to me, but I didn't feel anything.

And then yesterday, we both had a lecture after I hadn't been in since the first week due to being sick, and he was there again and he's suddenly lost so much weight and looks just like he did when we were going out with eachother, and I think I'm falling for him again. He was hanging around me during the break but didn't say anything but I could tell he was deliberately going near me. It is absolutely crazy coz when I found out he would be on the same course as me (a few days before I started) I was like nope, I won't get back with him, and genuinely had moved on and I couldn't understand what I used to see in him. But now I see it.

We even went to the same sixth form by coincidence but I didn't find him attractive then as I was so distracted with my last ex boyfriend. I've only ever had 2 long term relationships, and those 2 were them. it was a long relationship but it wasn't a horrible break up, theres no hard feelings unlike my last ex.

The ex and I have both had boyfriends and girlfriends the past 4 years but I just think its mad how we've been thrown together by chance in this situation and I, as stubborn as I felt, am trying to fight feeling this way but I can't help it. We had the best summer together years ago and some of the happiest memories were with him, in fact I think it was one of the best times ever. Just wondering if anyone could shed some light on this, are coincidences just coincidences? Or is this some kind of sign? Fate?...

by the way this sounds like i'm really vain, i'm not - when we first started going out years ago he wasn't good looking but i fell for his personality and charm, i really liked him. it was just he broke up with me back in 2007 and it was kinda mutual anyway after being together so long and we were only 15. then i convinced myself in any way possible to get over him ie. he went fat (i'm not really that shallow though) but it worked, i just thought of any flaws about him to get over him, i also thought of him as annoying etc. and i did get over him. but i'm remembering how many great times we had together and just getting butterflies in my stomach about him all over again its crazy.

Sorry its so long!! :( BASICALLY

1. We havent seen or spoke to eachother since 2009. (We were at same sixth form, not same courses though)
2. His looks never bothered me I just pointed out flaws to get over him because I used to love him and had to get over him.
3. His looks got worse, but has got his hair cut and lost weight and looks just like when he did when we were going out years ago.
4. He's had serious relationships since us, and I've had a serious relationship since aswell.
5. Now we're in the same course at the same university.

Thanks for reading :D! xx