Venus in Aries opposes Mars Rx (at 9 degrees Libra) on May 11th, along with the transiting Moon in Libra (conjunct Mars) to add some extra energy on that day. But the influence is being felt already, because both Venus and Mars are intensified.
They are in each other's signs (also known as mutual reception). Venus rules Libra, Mars rules Aries, and they are having a conversation. However, this doesn't mean that it's a harmonious exchange. Mutual reception amplifies the energy of each planet; they feed off each other. Mars Rx in Libra may indicate delays, but it's also about pushing beneath the surface to address what you're really angry about. There's frustration, because you can't take direct action, or because you've been evaluating your actions forever. And then Venus in Aries triggers that opposition. What you want (Venus) triggers actions (Mars) that have been frustrated. Delayed actions (Mars) must be balanced with the need to go after what you want (Venus).
There will be results or endings or clear-the-air confrontations. This may be the release of what's been building since Venus entered Aries, or since Mars went Rx. But there will be a release. I see this as a chance for Mars Rx to (finally) blow off some steam. It won't be smooth, but it will be honest. Many relationships will begin a new chapter, and I'm not using this as a sugary euphemism for "breakup." Sure, there may be some breakups, but there's just as likely to be an essential argument that puts the two of you back on track.
The theme with this opposition is what do you want, what's being denied/suppressed, and how do you deal with denial? How will you assert your values (Venus)?
As for how all this factors into the transiting Nodes in Libra/Aries, consider how you're pursuing what you want. Or even...if what you want is worth pursuing. Remembering that the transiting South Node (in Aries) is about actions (Mars) that don't serve you anymore, what new Venus-themed desires (money, attraction, relationships, self-esteem, values) are being stirred up? Are you taking the same old actions and expecting new results? You're not denying the Aries section of your chart, you're just moving away from actions that have always caused you pain/lowered your self-esteem. Venus crossing the South Node (on May 27th) will be a major release point for all that old, South Node stuff, and I'll write about that closer to the date. In the meantime, click on the link at the top of this paragraph to refresh your understanding of the transiting Nodes in Aries/Libra.
On May 14th, Venus will confront Pluto Rx (in Capricorn) with a square, and will conjunct Uranus on May 15th. May 14th is also a Full Moon in Scorpio. Lots of goodies being stirred up there, and I'll write about that in a few days.
If you have natal/progressed planets, angles or Nodes from 7-9 degrees of the Cardinal signs, you'll be ready to let 'er rip with this opposition.