Why He did not confess his interest or ask me out?

I've work with him for 5 years and sometimes I do feel something but i brush it off since I'm in a relationship. As a co-worker, we argue a lot, helped each other a lot but we were never close. Recently I've noticed this Libra Guy act flirty such as lightly touching my knee, thigh and hips which he has never done before. I let it off because i am his senior of 5 years older. One day i saw him looking down and sad, i approached him and we talked about it. He brought me to the corner of the office to talk and it surprise me he open up his problem and concern. I still brushed it off like nothing happened because its not like we were friend outside office environment. But due to this he start to text me or call directly which he don't do it so often in the past. Then came my birthday, he arranged a very belated birthday surprise with others co-worker which caught me off-guard. I was stunt but touched by the grand gesture, however a few funny remarks was the cake has LOVE on it and there is no candles? Yikes..i was like wth with this birthday? You guys didn't even sang for me of let me blow a candle— Anyway the dinner was expensive and he choose my fav cake and nice gift. He really swept my feet off the ground and kept me thinking what's going on with this Libra guy— (Yep this is why I'm writing this). I am confuse because he didn't even confess his interest or ask me out one- on-one.

I broke off with my ex last year but i only tell close friend (He is not included). I've told my female friends about this guy and they made a joke that if a man really interested in me, he will be there for me when i do my medical surgery. Yes he did, out of all men wooing me...he came in style at the right time. His bff is one of my close friend and he actually ASK him to come and visit me first but he declined saying he is busy. The bff end up coming alone with cupcakes to cheer me. On the last night my hospitalization, he came...ALONE..very late..he walk in smiling and chat to me until we're both sleepy. I did ask him to stay for the night since it's very late almost 12AM. He didn't say yes or no but laugh. Hurm ok... we chat again...when he finally make his move to go home, i asked him again He can stay if He want to...He just grinned and laugh, saying goodnight and off he goes.

So Why is he doing this and not upfront with it?
Me: SUN ARIES, MARS ARIES, VENUS TAURUS
Him: SUN LIBRA, MARS ARIES, VENUS LEO

Ok so i just have to tell him im single and let see what he gonna do?

You DO realize that Libras are flirty/charming by nature and it doesn't necessarily mean genuine interest, right?

sounds like you are friends.

hurm thank you all but yes i realize they are flirty/charming by nature that is why i brushed it off for the past 5 years i've known him. But the recent attitude towards me is new such as touchy touchy and talking more. At one occasion he held my cheek when whispering in a meeting with board directors. I was surprised but i can't slap Him in front of everyone. To get my attention, instead of tapping my shoulder, He would tap me between hip and thigh. Of course if this continue i can tell HR it's a form of sexual harassment in the office. I do realized he doesn't tap other female colleague like he did to me.

We were not in a good term in the past and our boss have to separate our location of projects so we wont bump head to each other and cause chaos/havoc in the office. Yep he is Libra but surprise surprise he can be aggressive and heated argument.

Fyi. We were never that "friend",

If he's not asking you out, he's not into you.

Yes, if he's still hanging around after 5 years, that means that he likes you, and if he threw you an office B-day party and footed the bill?, then he really likes you. Even as friendly as Libra's are, he's doing the most for just an "I like you/flirty" relationship. Like Champranger said, he may think you are still in a relationship so his high and mighty pride won't allow him to ask the right question out of fear of rejection. Plus, you're an Aries. Aries and Libra will always bump heads, but there's something about the chemistry that we have with Aries. Can't explain it other than a love-hate relationship most of the time, but one thing I have noticed is as we age, we seem to get along a lot better..well, at least for me that's how it worked. I think when both signs are young, they are very hot headed and stubborn, so the mixture is combustible.

Since i'm recovering at home, i contacted him last night asking about work. He indirectly ask me out after i'm recover from my medical treatment.