Thanks, SteelRose, hereiam &Echo!

Your feedback is right on point with my gut feelings. I probably wouldn't feel as strongly against SD moving in with us, but I am not able to forget her horrible behaviors, manipulating personality, and past troubles.
A little more on SD25's background- she lived with me for almost 2 years when her Dad & I were just dating. We lived in different parts of the state and he basically begged for help with her and shipped her off to me because she was not getting along with his side of the family (MIL, BIL, SIL) and was getting into trouble with her mouth, bad attitude, drugs, partying, etc. The rationale was that she'd clean up her act and not be around her druggie friends, etc. It only worked out at first, then went back to live w/ her Dad & my IL's... Until she failed her drug test, then he shipped her back to me. Few months after that, she got in contact with her BM and said she wanted to visit/ spend 2 weeks with her. BAD MISTAKE. BM is an alcoholic, cheat, sleeps around, etc. I cried because I knew the time and effort I invested into trying to help SD was going to go down the drain. But I couldn't stop her, she was after all 19 years old at the time. Fast forward, over the years, she's had serious issues with hardcore drugs, violence, changed mind on schools, careers, etc. NEVER finished a complete semester of college (and mind you, we're talking about 3 different schools/colleges), never held a steady job, etc. Did I mention that DH & I are still paying off a school loan of hers? Ggrrrrrrrr!

She is soooooo unstable JUST like her BM. Over the years, we've helped her in all ways possible- emotionally, financially, etc and I am EXHAUSTED!

She is currently living in another state and wants to move in with us because she says she needs help and needs us to teach her how to be a "good parent". (Her daughter is 2 going on 3 and is a lil monster!) She's burned bridges with her boyfriend/ baby's daddy and ruined her relationships with other family members in that town/state. They really don't want her there or anywhere around them...She's just toxic like that. Seems sweet & agreeable at first but her habits and evil temperament always end up coming out. She has always been the type to mooch off people for her benefit: housing, car, money, etc. Right now in her predicament, she has no where else to go. Currently staying with other family members who are tired of her crap and want her to leave ASAP.

I've tried talking to DH about how long she would be living with us, he figures "until she can stand on her own 2 feet". I say bullshit! She's never gonna be able to because she'll be too comfy with us providing a roof over her & her daughters head, covering necessities, etc.
DH knows I don't like it, knows I'm not comfortable with it, but already has decided that she's coming. It's hard for me to throw a fit and say "Absolutely Not" because we' ve helped out my own niece before. (She lived w/ us for 2 years while finishing up her degree). I don't want to be a hypocrite & only extend help to my side of the family...And I know he will point it out if I refuse SD.

I do have a personal wine reserve but haven't touched it since I'm breast feeding... But I can so see myself weaning my baby just so I can bust out wine glasses on the daily! Ugh! FML!

I would never ever put him in a situation to choose between his daughter or me. And if push came to shove, know I won't be able to kick her out... I'd rather take my own BD & BS and move out and away... I've been a single mom before and I sure did handle everything on my own. If I could do it then, I can do it now!... But I do love DH and our BS is only 6 months old... I'd really hate to do that. (Leave DH because of SD issues.)

P.S. SD25 has had many opportunities to move back in with us, but always ended up changing her mind because she didn't like our house rules, or telling her what to do. - Even if it meant how to appropriately take care of her own kid.
I've been lucky to dodge the bullet oh like almost a dozen times. But this time, it's actually going to happen. She has no where else to go and nobody is willing to help her out. DH is flying out to her next month to pack her shit & help her w/ her move here. Like I said, she's still DH's "baby girl". Her druggie, whorish, violent past doesn't faze him one bit. Even though SD is a manipulative little b$#%^, her Dad always has a soft spot in his heart for her. Makes me wanna puke!

I can't help but feel like she really does not want to stand on her own two feet and would much rather prefer to find people to benefit her or
take care of her needs (physical, financial, etc).
I've tried directing her to places/people that she could get help, but she chooses not to do her own legwork.
Prime example: She had a case worker assigned to her who was fabulous about reaching out to SD. SD would blow her off, not return calls, etc.. It was so bad! The caseworker, (bless her kindness!) would even resort to getting in touch with me (although I live several states away)
so that I could have SD show up for appts or at least call.
SD would have had help from this caseworker in getting benefits- housing assistance, emergency aid, childcare assistance, Medicaid, etc...
But what happened? SD is just to darn lazy and had 101 excuses why she couldn't make the appts or call the caseworker.
It's as though holding her hand is not enough, that you have to do things for her. Ugh!!! The more I think about SD and remember all the crap she's pulled, the MORE I DREAD her moving back in w/us!