Most relationships would last a lot longer if BOTH parties continued to put in the effort they did at the beginning.

I do not mean expensive dates but the effort. Talk to each other not other people when you have problems.

Spend quality time together. Living together can seem like a lot of time but you still have to put the effort in to make it quality.

Actually talk to each other

Have sex

Have date nights

Both make each other feel special

Remember when you thought the other person was the most exciting person in the world