If it was me I'd appreciate the alone time, or if I felt like going out, I'd use the fact I've not got an evening and grab one of my friends and do something.
Finding and keeping friends is hard. You get to see your significant other every single day if you live together, but maintaining friendships is actually more difficult for a lot of people. I tend to ditch my husband over "soft plans" all the time to do stuff with a friend if they feel like doing something because that friend often isn't available and my husband and I can do what we want every night of the week. Obviously I wouldn't ditch actual hard plans though - that is scheduled plans to go out, do something specific rather than just "catch a movie on TV".