He never actually says it…
In fact, she's not sure when it started. His "I'll chat with you at the office" turned into "I'll come by your house to discuss that client." Once that became something near a weekly occurrence, he added "I'll bring dinner."
At some point, she became so accustomed to it that she expected it. So the first time he conveniently "forgot" to bring food when the kids weren't there, the only option was for him to take her out, until he was always forgetting and taking her out when the kids weren't there (and he always knew exactly who he was feeding, even if it was her mother, which, at some point, stopped being creepy). So that became a near-weekly occurrence her children (and mother) labeled date night (though not while they were both in the room at the same time).
But he continued to be around for family dinners too. At some point, it occurred to her to ask Ray J and Lindsey how they felt about it. They said it was better than some options. Plus, he made her happy.
And he did. That was how he said it, how she eventually got the message.
How he did it, she didn't know. But he always could. If there was some event she would love to go to that sold out too quickly, he could get her tickets (and go with her of course). That restaurant she'd been dying to try for months, the one it was impossible to get a reservation for…he could do that too (and, of course, take her). The necklace she saw on someone once and fell in love with, the one she could never find in a store…well, he could (and have it neatly packaged for her birthday, which she hadn't told him about).
That was the real kicker…she never said anything, but he always knew.
It took her far too long to figure it out, but once she did, she knew she didn't have to say anything. All she did was take his hand at dinner. He smiled and squeezed her palm gently.
Some things are just better left unsaid.