First, bot games are great for three things: they let you get the hang of a champion's mechanics, they let you learn to jungle a champion, and they let you get that First Win of the Day bonus out of the way. You will not learn to be a great Varus, Vi, Karthus or Xerath without mastering their Q: it's important to try out Skarner Jungle a few times to see how to do it best: FWoD is great IP. Otherwise, these games don't teach you too much, so I'd advise against relying on them.
Second, what level are you? This will help us determine where you're at. You may provide your fiance's level, so we can analyze the difference. It wouldn't surprise me at all if he's caught on right away because he's got a longer background in playing similar games, but of course that's a baseless assumption, so explain if you'd like.
Third, if you have questions about a specific champion's role and how they fill that role differently than other champions, we'll be happy to explain. For example, Ashe is among the lowest DPS in the ADC role, but her utility is among the best. I'll explain that in more detail if you like.
Fourth, it's best to play with 4 people you already know. I'm glad you're playing with your fiance, but if either of you have other friends who play the game, practicing as a group of 5 is ideal to make sure you know that the people in the game are familiar with your skill level, supportive, and won't accuse you of dragging them down. Another asset is a voice program that lets you communicate with the friends you're playing with via headset. If you've got a headset but you don't have many friends who play, I might be able to introduce you to some amiable people I've been happily playing with for months.
Finally, persist. There are strategic skills in the game that cannot be taught. Eventually, the laning phase ends: how do you know it's over, and where do you go from there? When do you try to take objectives like inner towers, dragons or inhibitors? Where do you put wards, and when you don't have enough ward coverage, how do you know when to walk back to a safer area? The more games you play, the more instincts you'll develop. I know this seems like you're not learning anything, but keep an eye on the minimap (and your teammates' pings, when they ping): there will come a day when you realize your Spider-Sense is telling you that the mid-laner is about to gank your lane, and you need to retreat. The best way to develop these skills is to use the death timer and post-game screen as opportunities to think "why did that happen the way it did?" I know that answers like "the matchmaking gods have put feeble-minded imbeciles on my team" or "the wrath of my opponents was unstoppable like a tsunami" will spring to mind, but there are usually more useful explanations to be found. Acknowledge the frustration, push it to the side, and analyze. This is another area where a more experienced teammate can help to shed light.
There's my advice! If that doesn't save you, tell me more about the problems you're facing and I'll try again.