The only advice I'll give you at this point is you just wasted 8 months of your life. 

I would chalk this up to experience and move on. They are not going to change in any way and I seriously doubt if you could put up with being left out of everything - I certainly couldn't. They have a life they are happy with, why would they change it? Consider what you represent to this guy - are you content with being there just for the sex? I mean, he's getting everything else from his daughter. Or do you want a deeper, richer relationship? Don't sell yourself short - you deserve more than the crumbs you'll get.

That's just so odd and weird.

But just to keep it short and simple, that's not normal from his side or the daughters side. Who needs or wants to be checking their dads outgoings, how much, what and who it's on? 
If he won't change, she most certainly won't, so it's not even a battle worth starting.
Chalk this one up to 'it's not you, It's them' and move on. Sorry for you have to deal with these weirdos xx 

If this is what's going on in the 8 months you've been on the scene and this is what you KNOW is happening, can you imagine what is happening that YOU DO NOT KNOW ABOUT?

Their enmeshment has been going on long before you made your way into each other's lives.This is an extremely unhealthy dynamic.

I don't mean to sound offensive, but at 8 months, why do you need to know about his (their) money? You mentioned they have a joint account and both their checks go there. Presumably she has some sort of income, so how is i that he pays her "everything?"

You know what you need to do. He already has a "daughter wife." The longer you hang in there the worse it will get. Be grateful that you are seeing things NOW, and not after you've got years invested like many here.

Move on. He's already got a woman in his life and she's not going anywhere. Not worth the energy, the frustration, or the fight.

You can ask him if his relationship with her will take somewhat of a backseat for yours. But in my experiences with humans throughout my 49 years....I'd say it won't and you're better off leaving now before you waste any more of your life on these two.

Stop wasting your time. His daughter is his partner and you would only be the concubine.

He has a wife and it isn't you. He isn't interested in dating you; he's only interested in boinking you. Since he can't bring himself to cross that line with his daughter, he's brought in you to do it for him.

It should creep you out that you're closer to his daughter's age than his and that he wants to sleep with you. You're a surrogate for what he can't have.

I'd move on. There isn't room in his life for a "real" partner.  Unless you are willing to always be "less than," this isn't the relationship for you.

And the answer from everyeone is YES!!! 

So why are you even wasting your energy asking us about future problems of his daughter giving him an allowance, moving in together, buying a bed, etc.?  

We've given you the best advice we could and have answered your question:  You need to end this relationship.  Run.

What advise would you give your bff IF she came to you with the very same situation?

Would you tell her to stay in the relationship? Would you tell her "oh honey this is normal"

Find another guy. This one is not available for a healthy, meaningful relationship.

Ok OP your just jealous. jealous of his daughter.

There that is what you want, right?

I think you should let him move into your house. AND put his name on your deed. I also think you should help pay his daughter bills.

I think it is great your boyfriend asked his daughter to help pick out a bed for the two of you. Make sure she tries the mattress...you did suggest that right? I would also make sure she has money to purchase sheets for the bed too..............dont forget those.

This is a great realtionship for you. Best wishes to you all.

Yes.  Leave.

I have to agree with the others.  There are red flags all over this. As they say love is not enough.  My situation wasn'r as obvious as yours but my DH was very enmeshed with his adult sons.  Couldn't get two of them to launch.  If I had to do it over again, I would have moved on right from the beginning as sad as I would have been because DH is a really nice guy  But the stress, lies, promises were just that.

If you don't RUN right NOW, you WILL regret it. This relationship has absolutely no hope. This relationship is like having a relationship with a guy that still lives with his wife but not in the same bedroom. He tells you they are just friends now and like a good friend his wife takes care of the finances.

Stop kidding yourself and get the hell out!!

If your relationship goal is to date and have pleasant outings with your bf I don't see a problem with this relationship. However, it is clear the daughter is there to ensure she maintains her inheritance and may not allow your bf to get married in the fututre. If you would like to marry a man this is not the relationship for you. Myself and a lot of my friends either control our parents money or have their legal trusts in place to assure the inheritances. The daughter will not be willing to let go of the finances, ever. Good luck to you. 

Ha! Ha!  "Myself and a lot of my friends either control our parent’s money or have their legal trusts in place to assure the inheritances."  The top 2% of the MEllennial generation?  With the richest 1% of Americans close to surpassing the wealth of middle class.  Not a category for most of us here, I’m afraid.  Either that, or there are way more DaughterWives out there than I ever realized!

If this is a real SM and you're really looking for advice, mine is to divorce him stat.