Rose quartz is a wonderful crystal and it can be used for love, self-compassion, self-love and more. It is very heart-chakra healing.
Honestly, it sounds like if you get rose quartz just put it in sunlight like on a windowsill for a couple of hours to clear its energy. Then give it an intention (for self-healing, self-compassion) and keep it on you. In a pocket, pocketbook, in your bra if you wear one, etc.
If you worry about it carrying negative energy – sunlight is great for clearing. You can also dip it in warm water with salt in it and then put it in the sun.
The rose quartz will likely help YOU with love on your end. It wouldn’t force your boyfriend to do anything.
With regards to your boyfriend – communication is key. Just say – hey you have been distant lately and I need to know what is going on. We are a unit and I can’t help you if I don’t know what is going on.