Focus on how you're going to go forward not on what you did wrong. It sound like you already pinpointed your problem, lack of exercise, now do something about it! Register everything you eat (preferably before you eat it). It'll heighten your awareness of your calorie intake and during the day you can no longer deny/runaway from the fact that your overeating.
Motivation really needs to come from yourself. From what i'm reading you focus a lot on outside factors. start doing is for yourself. Motivation from outside factors are short burst, motivation from yourself lasts longer. Learn to motivate yourself by learning what matters to you.
Stop worrying about your boyfriend (it'll just make you wanna snack the worry away). What's the worse that could happen? Him noticing? Then tell him you know, you're disappointed about it and you're working on it. Try to turn it positive. Maybe plan some active dates. Go skating, cycling, take a walk on the beach/in the forest.
About exercise, try putting everything ready the night before. Wake up, put on your work-out clothes, have breakfast and go do it! Get it out of the way first thing in the morning. When i was unemployed it really helped me to get up on a decent hour and start active. Once you're on that couch it's hard getting off, so don't sit on it untill you did what you wanted to do that day.
Something else you can try is start with doing chores around the house. Clean your room, tidy things up, vacuum, go groceries shopping (with your mom?). These are all easy ways to burn some calories and make the people you live with happy at the same time. Usually when you get up and start to do something it's not such a big step to keep going and remain 'active'.
-I’m not 'losing' weight, I'm getting rid of it. I have no intention of finding it again.-
-It's not about how you look, it's about what you see.-