Your in a tough situation because your emotions are strong, and are especially strong for the other person you mentioned.
They are asking you to wait for a good reason.
And, how were you initially associated with Gods people..What was your initial motivation..? to study at greater depths, mature, advance spiritaully. or
to seek out a life-long partner..?
My only suggestion, and this is just a suggestion, your personal matters are yours alone.
Allow time to let matters settle with all involved, you, the other person, the congregation and so forth. Dont rush. Never rush a life-long serious commitment.
Continue to do your Bible studies, meeting attendance. reach out for the ministry. In a short time the other person will show their true loyalties, and with both spiritually mature your wait will be blessed and no futher problems from others who are at present trying to give a frustrated advice. ( Good intentions and all).
Scripturally you are , all are required to "marry only in the Lord". or within your faith. A famous Radio Mental Health Doctor will often advise her listeners to marry only within ones faith. If you are honsest and truly wanting to no longer associate with the congregation and fulfill your duties as a desciple of Christ and be known in the community as one of Jehovahs Witnesses. please do not add to one mistake by compounding it with another. The other person may likely return back to Jehovah's Witnesses at a future date and then where will yo be...?? Stay if you honestly and truly believe this is the Truth, otherwise you may be best served to leave the matter and not persue this other person. Or, do greater research with a mature sister you trust.