The girl I'm with wants to marry me, our relationship is great. She talks about me 24/7 to her friends.

But I'm unsure if IM being insecure for nothing.
She had a boyfriend 10 months ago.
-They were going out on and off for 4 months
-They nearly had sex towards the end of that time, but didn't because neither had protection
-She sometimes brings him up in conversation, always negative...but still he is brought up nonetheless like "Guess who I saw at the festival -_-" etc
-She sees him once a week as they share a class

And I feel quite threatened, because she is head over heels for me, it makes me wonder how much she liked him. She claims the two were never close and he was very hurtful and cheated, but I worry that because he was a total jerk she was attracted to him and still is.

How can I tell if she is?
I over analyse things she does...like for example she had a bottle of sprite, and during the class he asked if he could have a sip and she let him.
She told me all this, and it makes me think a lot.
She is *very* negative about him, and that's what worries me most.

Imaging you were him, would you want all this negative shit said about you? Another note, 10 months is not long at all, can you just move in with her and ride that for a bit? As for her still into her ex, I have no idea.

If she loves you, DO NOT be insecure, as this is one of the easiest way to lose her.

you carefully need to look at the following:

- how did they break up? did he break up or was the break up initiated from her side?

- how did things start off between you? was it the usual "falling in love process" that you can make sense of on a rational level, or was she istantly in love with you head over heels? the more it is the latter, the greater the danger that you are in the midst of a rebound.

- talking about someone is like having someone around. if she is completely over him she will feel indifference, if she hates him there still is an emotional connection of some sort. the more she tries to bring him into discussions for no clear reason, the greater of an indicator it is that she wants him around/still has a connection.

- is she actively trying to avoid seeing him/keeping it as rare as possible, or is she engaging in activities which could lead stumbling into him?

4 months isnt a long time and if its 10 months ago, well...

good luck!

Hey thanks for getting back to me guys

-It was mutual

-The process was quick, but it seems logical still. Although she DID say "So are we pretty much official?" after 2 weeks of dating. I don't know if that's a bad sign.

-She doesn't really talk about him that often now. In fact, I bring up my ex more than she does her ex - even though I don't find my ex sexually or emotionally attractive anymore. When he is brought into conversation it not usually to talk about him or his qualities, but if she's reminded about how she was hurt in the past she will be like "ugh, that reminds me of when he cheated" or whatever.

-I'm not sure if she tries to see him, it doesn't REALLY seem so. Only at college when they have to see each other. In fact when she's seen on one occasion him in public she has tried to look away until he has initiated apparently (according to her and her friends)

The only REAL red flag which I can sort of relate to Kathleen, is that she did fall for me very quickly, I must admit. So did I for her, but I mean we were telling each other "I love you" by one month.
The other potential red flag is whether or not she tries to see him on a subconscious level. Consciously, she tries to avoid him. No proof obviously, this part is obviously my insecurity.

Good news is that a female friend of mine was having troubles with her boyfriend, and my girl told her (according to my female friend) "He's not the right guy for you. Trust me you will meet someone who you really deserve. I had an experience with a guy who was a jerk, but we all go through that"