<human>: Can you summarize the given text in a few sentences?

Hi everyone, using throwaway account for the sake of.

So, I'm a male almost 25 yrs old guy who's been dating and engaged with a 23 yrs old girl for about 3 yrs, and we're planning to get married in the late 2016.

I can say I was raised without a father, since he was an alcoholic and left my mom when I was 10. I have 2 elder brothers and 1 elder sister who are already married, so things are a bit "I'm my mom's husband" sometimes. I really appreciate everything, every sacrifice my mom did to me, but it's about time to fly away, and this is where I need advice.

Well, because I was raised by my mom only, I'm not really the kind of decision-maker man a man is expected to be. I admit I fail to even argue against my mother or my fiancee, not because of affraid (far from that), but I just can't help suiting all tastes whenever my mom says something me and my fiancee don't like or when my fiancee is not pleased with her mother-in-law.

It's been a walk on thin ice to deal with these two women in my life, I love my fiancee, I know I must counter my mom when I don't, but I need some advice in here.

My mother sometimes says: "I think I'm gonna die of starvation when he leaves..." + "I hate being lonely" when she talks to random people at home, and on the other side, my fiancee just break me down whenever I don't have an attitude, like countering my mother whenever she trashtalks, even tho I like to think it's not on purpose.
<bot>: 25yo guy raised by mom, leaving home in the next 2 years wants advice to gracefully help her not panicking/get depressed when leaving home