Focus On Things Other Than Food
When you're eating out, I would suggest you focus instead on other things. Consider what eating out really means to you apart from the food. Perhaps it's spending time with friends, letting your hair down after a hard day at work, or relaxing and chatting with your partner.
Enjoy Your Company
Decide what your main intention is and focus on this, enjoying the time as much as you possibly can, rather than focusing on food. I see many people eating out socially and devoting so much thought and energy to the foods they're eating or not eating, that they miss the reason for going out in the first place.
I'm not suggesting you eat anything and everything you see, just that you allow yourself to enjoy the occasion and naturally choose the healthier options you feel ready to select.
Stick To Your Intentions
So, I suggest that prior to eating out socially you ask yourself "What's important to me about this time?" Then, create a way to remind yourself of this intention. Perhaps repeat it to yourself before going out or raise your awareness with a visual reminder. Ask yourself "What shall I do when I catch myself focusing on food more than I intended to?"
I also encourage you to make this a fun-time. When we feel more light-hearted about doing something, it tends to be much easier. What will it take for you to have fun with this?
Sharing Food Is Fun
Sharing food can be fun - sharing a dessert is one way of having fun and perhaps not eating as much as you would normally. I suggest you do this with the intention of having fun, rather than cutting out food of necessity.
When your focus and intention is taken off food and put onto other things, you'll naturally eat less food. You may also find yourself enjoying other peoples' company more and having more fun.
When you feel ready to make healthier or different choices of food, then take small steps, one at a time and don't feel under pressure from others or yourself to do it when you're not ready. Enjoy your life fully and let the weight loss happen gradually.