Of course yes! I understand is natural for someone to get excited about a new love interest, and therefore devote most of their free time to them in the beginning. However, they shouldn't left their friends behind. Like everything else in life, balance is the key!
I mean, seriously! Ignoring your friends, ignoring your friend's birthday (even there's notification on Facebook that would remind you few days in advance), get angry with them for trying to get in touch, really?
True enough, sometimes it is hard when we first fall in love with someone to even think about spending time away from our lover and with our friends instead, but we must never forget the importance of maintaining all of our relationships. A true friend should be treated as a true friend. And hey, if one day your significant other cheated on you, who else is left to be with you? And seriously nowadays cheating is such a common thing in the new era! (No offense, I'm not one of them :)
Never ignore your friends because you have a relationship.
In short, your friend shouldn't completely abandon their previous life in order to spend time in their new relationship.
Maybe is a problem when you completely ignore your friend when you're in a relationship, but comes crawling back each time when you're single again, that's a problem. Or are you that person who use friends as "something to do" until they meet a romantic partner are missing out on a very important part of their emotional life?
Seriously. It is worth it that you'd throw away a long time friendship just because you have met someone new in your life? Or you gonna replace your significant other's BFF as your new best friend by ignoring your old friends behind? Think about it.