Hi and Welcome
I really sympathise with the IVF as we did 2 years (5 years of trying all up) and my weight got up to 76kgs which is the heaviest I have ever been. Previous to trying for a baby, I was pretty much always slim-normal weight and very active (I was a bit chubby at a few points though) but IVF sent me into this awful downward spiral as you're so nervous during the end of a stim, waiting to hear about embryos and TWW then if you do get pg, you worry if everything will be ok (in my case I had 3 m/c's) so you eat! Then when things go bad, you drink! They tell you only light exercise but as I have been into high intensity exercise most my life, walking and similar is just boring for me personally, so I did nothing! It is an incredibly hard time to lose weight, so you have my full support and empathy with excuse #1 !
I think time constrictions really do exist, but I also think you can get one hell of a workout in in just 10 minutes if need be, 20 is better, but 10 can burn a good 100 calories at least at the right intensity. And EVERYONE has 10 minutes.
Buy a skipping rope - this is excellent exercise. Youtube 'skipping exercises' to get some ideas and then just practice till you get it. You might be buggered after just a few minutes to start with, but once you can master it, 10 mins is a great little workout. You will probably need to have breaks every minute or 2 to begin with, just keeping moving while you're catching your breath and do things such as jogging or marching on the spot, half push ups, sit ups etc. I bet you will be huffing, puffing and sweating after 10mins if you really give it everything you've got!
Then you can mix things up and the following day to a routine such as:
10 push ups
20 mountain climbs
10 jump squats
10 push ups
20 knee to elbow crunches
Go hell for leather and do it 2-3 times if you can, with a warm up and warm down consisting of light jogging or skipping and stretching.
Just tell yourself with the exercise that EVERYONE HAS 10 MINUTES on the days you want to excuse yourself from it. It will get easier and more fun and you will be looking for ways to challenge yourself. On the days you want to walk for an hour or do something else then take advantage of that...after a while, a 1 hour walk will appear to be much easier than a 10 minute hardcore routine!!!
With your boobs, i've been nothing bigger than a D cup so I can only imagine the discomfort. Go to a lingere store and ask them what the most supportive bra would be and get fitted for it. Chest exercises with weights would also be really good for you to strengthen this area while at the same time toning it.
Can't help with the chocolate addiction as I allow myself a small amount of choc everyday. Usually 2-4 squares from a block...that way I dont' feel deprived and it isn't a huge amount. I go harder on the exercises to compensate.