I am really close to an aries too, shes probably my best friend and its weird because apparently aries and capricorns arent a good pair and get on each other nerves easily (jst like you and your bf probably do) and i feel like with my aries friend as much as i love her she can also get a little too much for me and a little too self absorbed but thats ok because ive grown accustomed to it.
I think overall if you are pretty used to an aries and know what to expect with them then you’re ok. You and your bf technically are one of the least compatible partnerships due to being completely opposites but everyones different and it also depends on your more specific birth chart like your rising sign. If you guys both be mindful to each others approach to life and always talk out your problems (if any arise) then you should be fine. Xx
This is pretty tough, and it is out of character for a cap to cheat especially when they were cheated on in the first place, but his birth chart must be influenced by other signs, thats the only way i think he cheated.
If you really do want to try and save the relationship (or rekindle it) i say give it a little time. Because time heals all wounds, and make him earn your trust again. Dont just give it straight back! But it also depends on whether he and his ex were a serious commitment. Even more serious than you guys together. I hope this helps, and good luck! Xx