Who you sleep with while single shouldn’t matter for future relationships. Sleeping with others as a way too cope with feelings isn’t the best coping mechanism as so you’ve stated it doesn’t make you feel any better. Find a better way to release your frustrations. You are free to move on and pursue other relationships but don’t pursue them just as a means to get over or wait for someone. Live your life don’t wait on someone to return your feelings. If the time for you both ever comes then let it, but don’t dwell on something that could or couldn’t happen. Live in the now.