I'm (25M) at a bit of a dilemma with my girlfriend (23F) about my living situation and don't know how to go about telling her the truth

I own a house, and my girlfriend lives with her parents, so she comes over to see me. The only problem is that my dad lives in my house and in the 3 months that my girlfriend and I have known each other I've told her that he's my cousin because I didn't expect us to become serious, and she wouldn't know if that were true because he never comes out of his room. I don't know at all how she'll react, but I don't think it will be good. She says I'm the one for her and I think the same. My dad got out of jail 2 years ago with a felony, is hardly employable, and bad with his money. I let him pay me only a small amount for rent so that he can save up to get his own place, but I don't see how that's possible and I fear that I'll have to have him live with me for the rest of my life or he'd be homeless. My brother has an extra room in his trailer and can have him help with rent but he doesn't want his kids to be influenced by him, so he has nowhere else to go. I want to be completely honest with my girlfriend about everything but I don't know how to go about this. I don't even know if I should tell her, not because I'm afraid of losing her but because I don't want it in the back of her mind forever (if we get married, if we travel together, while laying in bed together) that I had my dad living with me in the same house the whole time while we had sex. I fear that this will put a huge dent in our relationship, and she's really emotional. How would you go about this?

TLDR: The 3 months my girlfriend and I have been seeing each other at my house I've told her that the guy living in my house is my cousin when in fact it's my dad. I want to be completely honest with her, but don't want it in the back of her mind forever. How would you go about this?

EDIT: Thank you everyone for you're advice. I will tell her and accept what happens. We plan on meeting my brother and his wife and kids next weekend so that I can introduce her, and then we'll park somewhere or go for a walk in the park alone where I'll tell her.

EDIT2: Actually I'll tell her before that.

Submitted January 20, 2021 at 01:41PM by Expensive-Winter4115 https://ift.tt/2LHnk7L