This is how we got started- he would give me scenarios about going for a girls night and meeting a hot guy, getting taken upstairs during a house party, getting taken on stage at a hen night, etc; and get me to do dirty talk role play, telling him about sucking their big thick dicks, fucking them, letting them cum inside me, etc and it always got him so hard hearing me tell these stories.
Next we started acting on this fantasy, small at first- sexting with guys from dating sites, sending them nudes, getting dick picks back and telling him what I was going to do with them, flirting with guys in bars while he watched, dressing slutty in the gym any time we went out of town.
Then eventually we took the plunge and I met a guy from a SPAM and gave him a blowjob, I took and sent a selfie during, filmed a bit which I showed him the next morning while telling him all about it. I was nervous it was going to break us but he has never been hornier. I have only done it a handful of times since but we talk about them all the time and both get off on it.