!! excellent pairing hmm.. compatible? yes- but i think whats more important is that you will compliment eachother/ understand eachother/ grow with eachother. but will take a little understanding early on. ill explain.
leo sun with cancer sun=PURRRFECT =D
you guys should compliment each other nicely... he understands you.. puts you on you pedastal =D (as you deserve) your security with yourself rubs off on him.. he loves your energy. high and deep is best way i can describe you
but early on he'll need security. NEEDS. lol. If you guys are "official" understand that he loves you already... show him how u feel for him, get to know his depth. and also cancers dont open up like that for everyone.. so its good that he has the moon in aries/ libra rising to help him open up for you. your moon (scorpio) and his sun (cancer) will relate deeply. your moon and his moon will respect eachother. (inner self/ reactions/ feelings) Soulmates? soulmates exist imo but youre talking about connection and companionship right lol? (this life) maybe im just a guy haha. relationship wise would work imo. and well it helps in this life that you feel deeply for eachother haha. your boyfriend has lots of potential in his life to be somebody great in his own right, be there for him now... and watch how he grows... he'll just give it all right back to you multiplied... remember you are the leo.

so... why does my opinion matter... cuz im a male with cancer sun/ aries moon. :D
btw you should have this posted on the cancer or leo tribe forum. remember... if its not about the aries sun, the people here with aries sun just dont care and wont respond lol (as seen)

good luck ellie!

yes. this can work. aries/virgo is good which are your risings. leo/cancer another good combo. i think you two could be fantastic