Like several characters in this book, Alfred Lammle is a no-good scoundrel whose only purpose in life is to serve his self-interest. Even after he realizes that his new wife Sophronia isn't rich like he expected, he remains calm and tries to see a way forward. No, the way forward doesn't involve love, just scheming. As he says to Sophronia,
I don't know. A mutual understanding follows, and I think it may carry us through. (3.7.110)
In other words, mutual interest is the closest Alfred can come to understanding the concept of love.
Alfred seems harmless at first, but we quickly realize how dangerous he can be when he threatens his wife Sophronia:
You have shown a temper to-day, Sophronia. Don't be betrayed into doing so again, because I have a Devil of a temper myself. (3.7.118)
From that point on, he treats Sophronia more as a criminal sidekick than a wife. It's nice to see Sophronia betray him, but in the end, the two of them remain stuck with one another, and they'll probably continue being con artists together in the future.
Oh, but at least Alfred Lammle beats up Fledgeby and stuffs his nose full of pepper. For one thing, Fledgeby totally deserved a beat-down. For another thing, stuffing pepper up your opponent's nose is just kind of an evil genius move. You get points for that, Lammle.