You may have to carry more stuff if you go alone, but solitude is a special reward and well worth trying at least once. The Rae lakes loop follows very established trails and would make an excellent choice for a beginner solo trip. Don't let your partner's absence stop you.

Very well said. Don’t let this be the reason why you didn’t go! The Rae Lakes Loop is a very populated trail. If you’re a novice backpack then I think this is a GREAT hike to solo on! Now, the question is just the added weight to your bag. Plan accordingly, and have fun!

Why not do it solo? Tons of people hike JMT and PCT, not to mention other backpaking trips, on their own. Plus, on this popular trail, you'll never be alone!

i might be down, looks sweet! let me ask my wife and my work and i'll DM you.

(worst case if you're sketched on going solo don't bail just do a shorter version or something!)