Reasons for passion's flame not so bright? (pt 1 of 2)

Hi there forum folk. I figured with my first post I might as well jump into the nitty gritty of relationship fun that is sex. :D

Here's the jist of my story. It is involved and a little complex but bear with me and see it to the end. I'm sure one of you out there has juggled something like this and has the insight that i'm searching for. I'm going to spilt it into 2 posts because of length. Sorry :bored:

I'm a 26 yr old "nice guy" (I hate it too damnit! lol) dating an 18 year old (named Joy) who is just finishing up HS this year. (Yes, I know what you're thinking) I just got out of a one year relationship and got burned bad by my ex who cheated on me with her ex of 9 years (Yes, I know I made a BIG mistake by thinking that someone with 9 years under her belt could just up and forget about the past) But anyway, I met my current gf at a party and found out about her age and we started dating not to long after. I really didn't want to get serious yet but she did. My reasons were:

1. My ex cheated on me with an ex (Joy currently is BF with an ex who she dated for about 3 weeks, but had extremely strong feelings for. Felt like a red flag to me)
2. She's only 18 and I didn't know if she could be mature enough to handle a serious relationship also stemming from....
3. Her longest relationship was 2 months. (I know she's only 18 but she's already dating guys in their 20's when she was jailbait so my age isn't a huge factor)
Before I was ready, she started telling people I was her BF. I confronted her on this and told her that we were just dating and she got defensive and upset. I explained to her some of my issues and why i'm not just going to do the HS thing of "dating me means we're bf/gf". She said she understood and I also explained of my apprehension with her keeping ties with her ex. (she's attracted to the "bad boy" types and has been cheated on, raped, played heatbroken by more than 1 guy, but only raped by her first serious bf (which I believe is the cause of some sexual issues) and she told me that sex to her is the bond that is strongest in relationships with her. I'm sure that's a reason she's been hurt so much. Unfortunatly, i'm the "good guy" stereotype I hate hearing about so much. The only time I wasn't that was when I had a short fling with this one girl and stopped seeing her for other personal reasons. (not playing) She has been lightly stalking me the past 2 years and thinks i'm some stud or something when I treated her kinda crappy. (so I guess bad guys DO get what they go for) But I couldn't keep doing that even if I wanted sex because it's not who I am. :bored:

I know she hooked up with me because she felt safe and believed I wouldn't hurt her and I haven't. The thing is, I can tell that her passion and excitement for me has died down quite a bit this last month. She still professes love for me and all that but I can feel a change. I ignored it with my ex and she went to seek whatever she was missing from her ex and you know...
Joy is more outgoing than I am but that's not to say i'm not. She's just into different things. I love socializing and i'm not the life of the party but I can get into groups pretty easily and end up being the comedian who people end up wanting to come back because I make them laugh. Joy is more extroverted and loves to dance and go clubbing and likes skateboarding and anything that seems exciting, but when we're together she can be soft and quiet. But I know she craves that excitement of a bad boy nature and I don't want to change just for that.
I've taken her places and our dates are hardly ever monotonous, but I feel like her passion is dying down and i'm not sure why. I think perhaps i'm TOO available, so i've been hanging around with my friends more often away from her. We see each other maybe 2-3 times a week but on the weekends, it's almost always the whole day. I'm trying to do more things so she sees that I do have a life besides her.
I was pretty co-dependant with my ex so I know what not to do with that and how it was unhealthy. I don't want to make that mistake with Joy. At first she seemed kinda co-dependant on me. Couldn't get enough of me, very jealous (but kept composure) when others girls (friends) talked to me, ALWAYS wanted and consitantly initiated sex before me. She is MUCH more sexual than I am. I have a hard time keeping up (almost literally) with her. I feel like I need to be a superhero to satiate her. :mask: lol (yes I know some guys would be ready to kick my ass over finding someone like her but I know there are lots out there.)

So what are the good points of this going into the start of 4 months? Well,
1. She has given me more affection/attention than any other of my past gf's.
2. She does lots of little things that let me know she's thinking of me (cards, poetry, pictures, phone calls)
3. She claims she's never cheated, only been cheated on (like myself)
4. She has a strong faith belief that matches mine and we share in worship together.
5. She is close with her family (although doesn't mind rebelling), her parents like me, my parents like her and have good feelings about her (as opposed to feeling right away that my ex was bad news. Of course I have to learn for myself but they were right in that case) :-P

6. She has girl and guy friends but alot of them have poor moral and ethical views (cheating, failing school, abusive relationships, etc)
7. We both enjoy and are attracted to each other on a phyiscal basis although I feel that she is moreso with the "attraction over time" thing.
8. From a sexual standpoint. We're pretty decent together but not 100% compatible. She's unable to orgasm oral which is unheard of with me. She's the only girl i've been with that can't do that. (but she has been raped and uses sex as a bonding tool also) AND, as far as she claims, she has been unable to have a vaginal orgasm (could only have clitoral ones with vibrators) until being with me. She didn't have one with me for about a month and said that i'm the only guy who has been able to do that do her and it was the first time she's ever HAD an internal orgasm. (there is a difference) It was actually kinda funny. She was like "Oh my God. NOW I know what all this fuss is about when my friends tried to explain how it feels." :D
And.
9. She feels that i'm the only guy she's been with that has made love to her as opposed to just having sex/f*cking. And that she's felt like she can be herself and not act/behave a specific way to keep someone liking her.

What are the red flags i've hit? *see next post* :)