You are more important than ever. I'm a uni lecturer at two universities, one extremely prestigious, one less so and what they have in common is students who do not know their arse from their elbows, regardless of their backgrounds, who are learning to be adults, struggling with miserable insecurities, and need their parents to provide comfort and a strong sense of home and stability in exactly the same way as kids starting school. In fact, prior to this job, I trained as a teaching assistant for reception children and I have used so many of the same strategies from that job in this one, you wouldn't believe. Your importance and parenting are absolutely crucial at this stage.
What you don't have to do is nights on sick patrol/ homework duty/ taxi duty and all the rest. So do what you've always done. Make the most of your time off, so that you can be there with tea, sympathy and patience when it's needed. And believe me, it absolutely will be. One of my best friends is 22. She is in her last year of a demanding uni course and has booked a term's worth of train tickets so she can come home and be with her mum, dad and new puppy every weekend. These kids aren't like we were, when we would have lived in a sleeping bag in a stairwell as long as we could say we didn't live at home anymore.
I graduated from an overseas university more than 20 years ago and one of the best holidays of my life, before or since, was my parents coming for my graduation and the three-week road trip we took after. My parents are not and never were cool and understanding. They are deeply irritating and we have always had very little in common. Who did I want there on that day? Them. Who did I want to share my experiences with, even though it was tempered with some difficulty because they couldn't get proper tea or a copy of the Daily Mail? Them.
It's never over. So take up tango and glory in the fact that your house is, temporarily, your own. You will be pressed into mum service soon enough, and dating is never going to compete with the fascination and fun of being a parent. In an ideal world, we imagine that couples who wave their kids off to university rediscover each other and start afresh living the hopes and dreams they put on hold while their families were young. In reality they realise they can't stand each other and have nothing in common. It's not and is never as cosy on Planet Couple as we single parents imagine.
This is a new and exciting phase in your life, and is likely to be short-lived as your kids return home after graduation because they can't get a job and all the rest of it. Have some breathing space, enjoy what you can of it, and brace yourself! xx