You say that your relationship is purely sexual, and that the sex is great. It sounds like both of you want a more personal connection, beyond physical sex–and that while you realize this and are open to it, he's probably very much afraid of it...or at least deeply conflicted between his idea of religion and his natural bodily attractions.
I don't think you can resolve his internal conflict--it's something he has to work out on his own. Until he works that out, I think it will be painful for you to be around him and not have things develop the way you would like. (I have been in this same position, and it's not pleasant.) I suggest that you tell him that you are open to a more significant interaction with him, but that you won't simply put things "on hold" and wait for him to come back after Great Lent.
This will be a difficult conversation to have, but I think it's valuable for you to stand up for your own feelings--and that you won't be controlled or harmed by him. He may or may not realise that he is also harming himself...but that's something he needs to take responsibility for.
Please let us know how this turns out. You sound like a sensitive, caring person who not only enjoys great sex, but sees the value of emotional attachment with another guy. It also sounds like you are willing to "attach" to someone who has different beliefs or ideas than your own, and that's a wonderful thing. But these characteristics can lead to pain if you don't actively take care of yourself. There are lots of wonderful guys out there with whom you can form a wonderful, and mutual, attachment.
