Normally Strange expresses his feelings with small meaningful gestures but he can be very bold when he’s too sentimental or when the ones he loves doesn’t notice the little hints.
Most people only go for the small meaningful gestures when they want to tell the other person they love them, but being in a relationship with Stephen would mean constant little meaningful gestures because he’s very sentimental and because his feelings are very legit.
Of course there would be days in which he needs some time for himself to meditate or to cope when things are too difficult, but when everything is okay, he’ll be a dork and a cutie most of the time, taking things seriously when they have to be taken seriously.
In the days Stephen is needing love, the loved one might hear “I love you” every half an hour, while in the days Stephen is not very okay, he might be silent, closed in a room for an entire day.
About considering himself a "romantic", yes, he does, and he is. Stephen is VERY sentimental. That’s one of the reasons he struggles after he has a casual night with someone. He gets attached while the other person doesn’t give shit.
One of the reasons he seeks physical love is to FEEL loved //what is an illusion//. Stephen is very emotional, he doesn’t want/need only physical love, but “spiritual” love as well, that consisting of emotional support, cute moments together, helping each other and intense, sentimental stares, dorky moments, making the person laugh, planning together, doing things together, working together. Maybe that’s how he started to fall for Christine, they are awesome as a team, they trust each other, they can read each other, they’re both intelligent and for some time, they shared a deep, emotional bond, but Stephen was too much of an arrogant, materialist selfish shit and Christine got tired of that. They probably worked together for years and he probably was working with her //emergency// and not in his neurosurgery business all the time because he wanted to work with her.
The same happens with Clea later on in the comics, they work very well together, they understand each other. So Stephen IS a romantic, being that romance awakening before knowing the person too well or after it.
Stephen tends to approach the person and try to be friends. Spending quality time with the person will make him really happy, even if he knows he will never be able to stay with said person //if they’re already married or something idk//. If he knows he has a chance of dating his crush, he will give some hints and ask the person out. If the person refuses or shows to be uncomfortable with it, he will be sad and will stop bothering, still doing his best to remain friends.
As the first FIRST reaction, Stephen might think if he has a chance or not with said person, then plan how he’s going to be nice to his crush, how he’s going to approach and hint.
The good aspects are that as a close friend who has a crush on someone, he’ll be patient, caring, dorky, funny and he will always be by their crush’s side in most of the situations //only not if the situation is too trashy or serious//.
The bad aspects is that if the crush doesn’t like jokes and ironies, they might feel annoyed. Also, Stephen can be a bit possessive, jealous if the crush is going out with someone else and he’ll try to solve all the crush’s problems for them //that can be good and bad//.
In general, he will be clear about his feelings, If he knows the crush doesn’t want him, it won’t stop him from being respectful, sweet and caring, but when he gets too sentimental, he might be too affectionate The puppy eyes and lil smiles might be quite convincing and cute and he totally means all the emotions and feels he has. He used to be a lot more selfish and arrogant, but apparently, that changed after the training in Kamar Taj.
A good example of the situation is how he interacts with Christine. She doesn’t want him anymore, he knows and he’s not insisting and bothering her to date him, but he’s afraid to lose her attention and her friendship. Christine didn’t push him away just in the romantic level, but she also pushed him away in the FRIEND level, she stopped replying to his emails, she stopped wanting to go to places with him, she started to cut every conversation he started and that made Stephen go crazy. He doesn’t want to lose her friendship, he doesn’t want to lose her attention. That’s why he’s so jealous of Nick, totally afraid he’ll get into another level with Christine, totally afraid he’ll get all of Christine’s attention.
Stephen loves her, cares for her and accepts to be just a friend, he keeps trying to show that, always giving her the message that if she ever wants him back, he’ll be there. That makes it really hard for her to break up with him because Stephen has so many cool traits, he’s open minded, he’s determined, he’s clever and funny, maybe that’s why Christine tried to break contact with him.