<human>: My boyfriend[21/m] and I[22/f] have been dating for two months and friends for three before that. Just like the title says, we are both very jealous people, but for good reason!

We're both pretty nerdy. He's big into Warhammer 40k, video games, and the like. I'm a tomboy who works at a board game store, consequently I have lots of male friends. Both of us are at least moderately attractive. I have had repeated problems with guys wanting to be friends (maybe even with completely pure intentions) then having some variety of crush on me. It's been a running problem.

A little back story! Before dating, we had almost gotten together before when I was between relationships. He expressed interest, I thought I wanted someone else, we stay friends but he's still interested, a good number of months later I'm single again, and suddenly he's an option again. And so we start dating! He has had (understandable) insecurities about my ex since then, we have discussed it in depth and it has gotten a lot better, but it's still something to consider.

Which brings us to our current problem, but first a few inalienable truths about our relationship: We trust each other, we want each other to have friends of the opposite sex, we are both equally jealous types, and we both don't intend to fix that. 

How do we express to all opposite gendered parties surrounding our SO or ourselves that they/we are off limits? How do we do this when it's just quiet crushes a lot of the time and they're friends of ours? We need strategy.

Can you give me a shortened version of the text?
<bot>: As a couple we are quite jealous, how do we subtly let single friends know we/our SO is off limits without being crazy?