Life can get in the way sometimes. I have been there myself. Sometimes it is very hard to make the right or best choices. Sometimes you just want that cheesecake or that creamy pasta or the frozen drink (One of my favorites is the Death By Chocolate from Segafredos). My biggest recommendation under these circumstances is: Try again.
Guilt will not get you anywhere. Blaming other people doesn't work either. Take responsibility and the next time you eat out, try again. Stick to the basic principles: Share the bad stuff, choose grilled over fried, don't overdo the bread basket. What's the point of going out if you can't indulge just a little bit? You can, but be conscious of what you are doing.
Most restaurants today offer a light menu, even the worst Chinese restaurant. Keep in mind that restaurant portions are often times twice or four times more than the regular portion (think Cheesecake Factory) and with four times the fat and calories accordingly.
Life is short, you can eat dessert first, just think which are the best options for you. If you fall off the horse, get up and try again.