Has your love life been a hamster wheel of the same romantic issues since adolescence?
Venus in your natal chart signifies (among other things) who you attract. When you're young, you use Venus's energy without thinking. For example, Venus in Libra attracts partners by making herself into who she thinks they (the other person) want. Venus in Scorpio magnetizes tons of romantic attention, but it's from all the wrong people. These are simple, less evolved versions.
As you get older and more self-aware, you (hopefully) gain control over your Venus. You start to manifest the advanced aspects of her sign. Venus in Libra becomes a balanced partner, attracting others through a complete awareness of their needs and her needs. Venus in Scorpio is more selective about who she magnetizes as she becomes fearless and profound.
But if you remain stuck with the original definition of your Venus, your relationships will never change. If you don't explore her full capacity, you'll keep manifesting the lower (less evolved) versions of the sign she's in. All the affirmations in the world aren't going to make a bit of difference. If this is you, the fix may be as simple as becoming fully aware of your Venus's potential. Figure out the highest expression of her sign and use it.
Now, this is a very general overview of Venus's function in the natal chart. The house position and aspects Venus makes to other planets will give you more information. But Venus's sign is a good place to start. If you're stuck on what the higher manifestations are, think of the best that sign can possibly be. For example, Venus in Leo shines as the center of attention. But she's brightest when confident enough to turn the light of her generosity on others.