She can't.

"I'm sorry, Lindsay. I wish you had asked me first before you talked to Horace. I just can't."
"Seriously?" Lindsay looked quite dejected, and a little disappointed. "Fine. I guess if you can't you can't. I'll call Horace and break his poor little heart."
"Ha. I don't think his heart is the issue." Beth tried to lighten the mood.
"True." Lindsay looked at her sideways. "Are you really set to just... let some guy rule your life? You're too young to just hand over the keys." She sounded actually frustrated now.
"That's not what I'm doing, Lindsay." Beth looked away from her friend. She knew the words sounded hollow. "He doesn't control me, I just don't want to do something I know he'll be upset about. It's called love."
"If you ask me, any man who neglects a women with your assets doesn't know anything about love."
"It's just for now. He's working really hard. Once he makes partner, things will be fine." Beth chewed her lip in frustration.
"If you say so. You know my feelings." Lindsay folded her arms across her ample rack.
"Yes, you've made them very clear. Just...be nice, okay?"
"I am. For your sake."
She left the lunch feeling frustrated. Lindsay made too much sense, and it was getting under her skin. She was a grown woman with needs and autonomy. It wasn't fair that she had to put up with this nonsense. But she loved Brian. Which is what made the whole situation unbearable in the first place. She did love him, and didn't want to.... aghhh!
In her confused and frustrated funk, she drove home.