Relationship problems

I hope someone can help because I'm getting really depressed. My wife and I have been married for over 4 years - it's her 2nd marriage and my first. We've had a really good relationship until a few days ago when something happened and I'm now really depressed about things and our prospects. So here goes:

When it comes to sex, my wife and I have had a reasonably good thing going. However, she's always had some hang ups about certain things - mainly because of her ex husband who forced her to do things. Armed with this information from day one, I've always been very patient and careful not to pressurize her into anything.

Now the strange thing is that, apart from the certain hang ups she has, she does have a healthy appetite for sex and would often joke about us stopping off whenever we passed one of those XXX Adult Movie type stores on the highway. I've always shied away from it in the past because I knew there'd be things in the movie which would be a gamble as to whether she'd gotten over the hang ups yet and I was afraid of getting a bad reaction.

Well the other night something got mentioned about getting a movie again and this time I decided what the hell I will take the gamble. Needless to say, we're sat in bed watching this movie and a girl goes down a guy and he releases himself into her mouth (sorry, I'm not sure how graphic I'm allowed to get on here so please forgive me).
My wife's reaction was that she got totally grossed out and said so right there and then.
My heart just sank! Seeing her reaction I said "so you'd never do that for me then?" and she just said "but that's totally gross!".

It was immediately apparent to me there and then that 4 years with me had done nothing to get her over her old hang ups. Now before you all start screaming that I'm selfish or whatever, let me explain a few things:

First of all, I wouldn't want to pressurize nor have never pressurized my wife into doing anything she didn't want to so please don't make an assumption that that's what I'm doing or going to do.
Secondly, I'd never asked her to do that to me in the past - I had just HOPED she would as it would be the "ultimate" thing she could do for me. However, regardless of where the stuff ends up in the end, she'd never done it long enough for me to even come close anyway in the past which has also been very frustrating but I never said anything about it.

So here's why I'm getting depressed (and there's several reasons):

1] I'm worried that my sexual prospects in this relationship have kind of gone down the pan.
2] It's made me lose sexual confidence and my personal self-worth and esteem have gone down several notches. It seems I have no way of driving her to so much ecstacy that she can do those things without the hang ups.
3] I'm feeling a little jealous of the ex husband who used to get his way but I don't - and because he "persuaded" her to do stuff, I feel like I'm now feeling the brunt of it all with the hang ups she has.
4] I never thought I'd say this but I'm now beginning to wonder if I made a mistake with this marriage. I feel like there's little point in continuing the relationship if I'm never going to be totally happy in the bedroom.

We've spoken about this but to no real avail. I can't get to sleep at night and I'm like a zombie through the day. If she ever did that for me in the future then I will always have it in the back of my mind that she's only doing it to pacify me and doesn't really want to - therefore there's no point in me asking or pushing the subject further. The whole "thing" has now been lost for me totally.

So now I'm trying to put a brave face on and pretending like there's no problem because I know that it will only make matters worse if we argue about it more. The thing is, it's really chewing me up inside and I feel like things are now going to get worse before they get better.