Two women, one possibly "Ms. Right", and one "Ms. Right Now"... what should I do?

There’s a woman I’ve been interested in for all the right reasons. Been dating her (and waiting – if you know what I mean) for about 1.5 months. I know I know… that’s not the point. Just as she warms up and literally invites herself over – I meet another woman who literally throws herself at me (remember my woman with tattoo on the back?) She is Ms. Right Now – and is so negative an energy that she literally zaps mine along with hers. But the sex… anyway… I’m a one woman kind of guy – so I had to blow off the first one… I said I had plans and such – til next week. She isn’t stupid… I don’t know… what would you do?