Congrats on your weight loss so far! I started the same time as you (this is not my first time around). I have lost the SAME amount as you
I have five young kids and it isn't always easy for me to follow 100% of the time. I try very hard though
I hit a bit of a plateau for a while and found that changing my exercise and/or having a "cheat" (like b-day cake or a b-day dinner out at a restaurant) actually jumpstarted the scale to go down again. I just made sure to drink A LOT of water during and afterwards and returned back to the beachy meals right after. I read about people going for full on cheat days and there is no way I could do that...it would cause me more harm.
As for the cake...is there any reason you can't ask your hubby what he's like? Maybe he is willing to try a SF cake, or a sliver of real cake, or icecream cake? Just make sure to get it out of the house AFTER the b-day so you aren't eatting the leftovers all week
There are A LOT of recipes for SF cake that use WW flour....TONS!!! Carrot cake, banana, cheese cake. Go on pinterest or google the type of restrictions you are looking for. Use spenda, agave, honey, or just banana or apple sauce as your sweetener. You could use cool-whip for a topping if that is your thing.
The first time I did this (years ago) I did all the sweeteners, cool whip, etc. This time we are trying to balance out real food (like a dollop of real whip cream instead of cool whip). It is a learning curve and my scale likes to tell me what doesn't work