I used to have the same association. Before I got together with my current gf, sex and condoms always went together. Now I don't need them with her (longterm, monogamous relationship; disease-free; other birth control methods). It is great not having to use them, but sometimes I still feel like I'm "supposed to." Ironically, just when I no longer need to use condoms, they finally come out with a brand that actually fits me! (They-Fit from Condomania.com that went on the market just last year.) I went through most of my condom-using life struggling with condoms that were too small.

Now, I sometimes masturbate with a condom for a change of pace and easy clean-up.