Aries and Gemini can be a very successful relationship. Aries is impetuous. It lives and loves its passions. It is spontaneous. Gemini also has an open and curious approach to life. So they can meld their energies well.
One of the perhaps difficulties is that Aries likes to lead. Gemini usually adroitly gets out from under any kind of orders that the Aries will give. But they can work this out, because basically they both have that same approach to life, which is an open one. Neither of them is closed in. Neither of them tends to be negative.
Sexually, they work out very well, because Aries again loves sex, loves the spirit of the fire and the passion and the impetuosity of sex. Gemini is very curious. So Gemini can be very inventive and can think of wonderful things to excite an Aries. Aries in turn can excite a Gemini, because Gemini is willing to experiment and explore practically anything. So sexually they are a good match.
Mentally, they are also a good match. It's the emotional part. If they can work out the differences between one being the leader and giving orders and the other one not taking them, then it's a good match.