Determination is contagious and it's only a matter of time until your loved one jumps on board with you. I have found that when I find myself getting up in the morning, the day's my girlfriend does not feel like going to the gym, she ends up coming along for fear of missing out. This is a good thing and it needs to be cultivated. By no means am I saying my girlfriend is lazy, but I'm speaking to the many of you who's loved ones are not interested in working out or changing their habits.
Health is contagious and results are even more addicting. Even if you are able to start by offering to cook healthier alternatives for your loved one, and asking them to join you for a walk through the development late at night. Anything is better then nothing. Just note you cannot force someone to do something they don't want to do. Be understanding, and sympathetic, but be determined and do not give up. Anxiety is often the hardest part for someone who is overweight to overcome.
This is the person you want to spend your future with, just be subtle and let them know that with small changes that forever will be even longer.
Recovery for two.