I think you need to think clearly about why exactly you are upset.
You seem to be angry on three different levels: one financially, another is the whole issue of pornography and how his interest in it affects your self esteem, and the third is the secretiveness issue.
Think carefully before you discuss this with him. If you are trying to save for large purchases and you have agreed between you on saving money, then his spending outrageous sums on pay-to-view is not justified.
The fact that he spent this money behind your back speaks to the issue of trust and deceit. You'll have tothink about how you want to handle this: do you ever hide things from him? If you do, tread carefully. If you don't, then ask him why he does.
But, what really seems to have upset you is how you feel about pornography. Are you clear in your mind about how you feel about it? You cannot tie your sense of self esteem in to your husband's consumption of pornography. You cannot keep working out only to make yourself attractive to him. This is not going to lead to a happy sense of self for you and is not good motivation for maintaining fitness in the long run. You should work out for yourself and to maintain good mental, emotional and physical health.
Why does his viewing porn movies upset you so much? It does not follow automatically that he is less interested in you sexually. It does not necessarily imply that he is immoral or exploits women through watching porn. After all, if you pick up any sex manual you will read advice to couples to watch porn together to stimulate their love life. That being the case, is it wrong to watch it on your own?
I think that what is interesting about porn is how it plays into and satisfies our fantasy life and sexual fantasies. Many women read romance novels, and there are some pretty raunchy ones in the genre, for the same reasons and needs. Are we then to say that they shouldn't because it is wrong to have a sexual fantasy life, one that may exclude or only partially include a spouse/partner? Men are visual creatures. Their desire to watch porn can be seen as the equivalent of women's desire to read erotic literature, for the power of suggestion, for titillation. But does it really mean that they value their spouses less? Maybe. But not necessarily.
The only problem with sexual fantasy is if it creates a disjunction between a person's real life and sexual fantasy life. If the fantasy should become more appealing than the reality, or make us disatissfied with the reality, then it becomes problematic.
I believe I would tackle the discussion on these levels: 1) if there was an agreement to save money, then why is he spending it so wastefully?, 2) why does he find it necessary to be so secretive?, 3) how does he feel about the sexual fantasy of porn versus the reality of his own sex life and rerlationship with you.
But one thing is clear: your self esteem ("working out to look good for him") should not be tied to whether or not he watches pornographic films. His fantasy needs or desire to watch porn films have nothing to do with you, in my opinion. If it is a problem at all, it is his problem.
Hope this provides food for thought,
Clare