Well I understand your concern and I hope you make the right decision, but you have to be realistic and keep things in perspective. Most people have the desire to have a mate or companion, but as with all things there are obligations. As a Jehovah's Witness your very first obligation is to Jehovah God. (Deuteronomy 11:1)
If we were to rewind 3 years back, that would make you 18 years old. Dating as you know is for Marriage. 18 IS a 'legal age' to get married, and even though there are 'some' exceptions to the rule (a VERY few) , your average 18 year old does not even know who THEY are, let alone are in position to get Married which requires a person to be emotionally, physically, mentally and spiritually mature.
So not to be blunt, but it seems that the situation you are in now is a direct result of a previous bad decision. So your problem is not 'now', it simple the 'result' of a seemingly unwise decision in your past. (1 Cor. 7:39)
Again, I am not saying this to be blunt, but because I do care, and it needs to be said. If he 'is against religion of any kind', your love is not founded on something 'realistic'. This does not mean that your 'love' is fake, or 'not real', I'm sure it is, especially if you have been dating for 3 years. But, what I am saying is that your 'love' has now blinded you from seeing things correctly. And that is not a 'well founded love', it is a 'dangerous love'. For example, there are people who are so SINCERE about what they believe, that they are willing to strap a bomb on their body, kill themselves and others. Is it sincere?? You betcha! But is it a 'well founded' belief??, obviously not!
The 'only thing that is wrong with him' as you state, is a BIG one. Spirituality is the MOST important thing, ESPECIALLY as a Man, being the 'Spiritual' head. You may love him and he may love you back, but he WILL keep you from progressing, because he already has.
Imagine where you could have been Spiritually speaking, now? Furthermore, if you marry him he will be your head.
Think about that seriously - Do you really want your 'head' to be a person that is 'against religion of every kind'?? If you have children (purposely or not) How will they be raised?? Do you think he is likely to let his children be raised in a 'religion' since he doesn't care for religion at all?? You HAVE to be realistic, and think about your future. There are people who DO marry in the truth, and STILL have major problems due to not applying Bible counsel. Realistically speaking then, do you really think you will fare better than them with an unbelieving mate?? Logic would dictate no.
Do not let your emotions blind you and take you down a road that will lead to you AND him missing out on Jehovah's blessing. There are MANY examples of sisters who came into the truth after they were married to unbelieving mates, and eventually their mates came into the Truth. But they did not recieve Jehovah's blessing by being disobedient to him, they did it BY being obedient and loyal to Jehovah FIRST, and Jehovah did the rest.
Whether the end comes tomorrow or 20 years from now, it IS coming to an end. Why live your life in a way that will not attract Jehovah's blessing?? The ONLY THING that will allow us to survive in the Great Tribulation will be our relationship and love for JEHOVAH GOD.
Thank you for clarifying the 3 years inactive things - you can thus disregard my comments based on that.
Side Note - I have many good friends from Cuba! I relate very much to the Cuban in my congregation very humble, upfront, sincere and fun loving people.