I showed off my bikini to my boyfriend at the wedding reception
That is very inappropriate. Why would you decide that was the right place to do that?
Oh yeah. He actually meant to propose to me that day, but I told him that I didn't want to get married just then.
It is good to show off to your partner in privacy. You should not make a scene at someone else's wedding by getting engaged that is tacky.
What if I just wanted to show off my swimsuit.
I can understand that you wanted to show your boyfriend, but that was not the time nor the place. It is okay to share a private moment with your partner, but not at someone else's wedding. Those things are best left in your own room or house.