I don't think it loses momentum as much as you think it does. It has rhythm that keeps it going.
I wonder about a couple spots.
1. "You're too cruel..." I'm getting an impression, from the lyric (possibly an incorrect impression, in which case, never mind) that the antagonist is too shallow actually to be cruel. I might substitute something like "vague" or "shallow" (but shallow has too many syllables, so maybe not).
2. "...why I let you / Let me down." You haven't set up a pattern of repeating words, so--if you prefer not to repeat "let", maybe you could use "get me down" or "put me down".
Just possible ideas, if they fit your vision. If not, toss 'em.
As you mentioned, there's no hook. Yet. A short chorus might be in order. The "nightclub bargain basement" line is great! It might make a good hook, but right now it's in the third verse, so that could be awkward.
Taking a hint from the "swallow someone new" phrase, what about a metaphor with the word barracuda? Or shark?
You're a barracuda. I shoulda eschewed ya (bad, bad, bad!) There's a surprising number of possible rhymes with barracuda, though. Tuna, tuba, loofah, Cuba, beluga, intruder, bermuda, hallelujah, etc.
Anyway, feel free to take advantage of anything here, if you like, or not. I hope this is helpful but, if not, I'll try again sometime.
Vicki