Honestly, If your Significant Other even dares to put you into that situation (No matter how long you both have been together in your relationship and no matter how many times they say "I Love you"), they never loved ALL of you to begin with because if they did they would never make you put the Lord to the test. So better just to end everything because they will not change, even for you (Or the so called "Love" they claim that they have for you) if they try to make you choose then over the Lord. Now if you're both deep believes in Christ then they may just be testing your loyalty and faith in the Lord for the good. But if they refuse to believe and love the Lord, then they're basically refusing to Love you also.