How to spice things up in a relationship help

So me and my boyfriend live 2 hour away we both work he works Monday/Friday and I work different dAys every week and alternative weekends which means we only see each other once or twice a month meaning there is usually 2-3 week gaps in between seeing each other. He has just messaged me asking am I seeing someone else because I’m not as fun as I used to I used to always send nudes and do videos and flirt and now I don’t and he said the relationship is losing it’s spark and going dull. I will literally have no one if he leaves me because I hardly have any friends and I don’t get along with my family. What can I do to spark it up i really want to make it work