Disagree!
The availability of contraception made the affairs seem inconsequential.
The abortion was the fulfillment of the promise of no consequence.
That is true, but does not make the case you are trying to make. Because people use abortion AS their contraception does not mean that other contraception LEADS to gay marriage. Keep your eyes focused on the ball, the topic at hand, and quit going down little tangental trails that don't speak to the bigger issue.