I am a Shia woman who comes from a very religious family. However I am in love with a Sunni man and would like to marry him. Should I teach him about Shia Islam and enlighten him as to allow him to convert? Or should I instead end everything with him?
Bismihi ta'ala
That is very good that you come from a religious family, and as a religious person you know what your obligations are.
In our Shi'i fiqh, it is permissible to marry anyone from other Islamic sects, as long as you are free to keep your Shi'i identity and uphold your Shi'i practices. You do not necessarily need to convert him to becoming a Shi'i, as this is something that comes from within.
It is his choice, if he is interested in learning about Ahlul Bayt (a.s.), and following the Imams (a.s.), or not, as long as he does not harbour hatred to the Ahlul Bayt (a.s.).
Something that you must keep in mind is his surroundings, and those influencing him. In some cases, the husband/wife might be neutral, or compliant, but then get negatively influenced by an extremist, or a Wahhabi, or a takfiri, and then this starts to have an impact on the marriage.
In early stages of life, he/she might not be that religious, but then after a while, they start to pick up on things, and condemn you for praying on soil, or mourning Imam Husain (a.s.), or wanting to go to Ziyarah, and so on.
This does happen, and so it is very important that both sides clarify everything and make sure there will be no sort of mistreatment based on sect.
Another thing that you must think of is because you are "in love", it might cloud your judgment as to whether you are making the right decision.
It is absolutely necessary that you consult with your parents, and also discuss things with your elders and family members, to make sure you have their consent, and also the decision you are making is the right decision. This should always be the case, whether the prospect spouse be Sunni, or Shi'i, or anything else.
So, if he has the positive requirements of a husband, and he meets all the conditions, along with your family's approval, then discuss that's a very good thing.
You can discuss topics related to Ahlul Bayt (a.s.), but it has to be his decision from within himself if he has the interest and wishes to learn more, or not. That must be his choice, and not something imposed on him.
With prayers for your success.