It sounds like you have a great evening planned. I have a 16 year old son, but I've never really thought of him as territorial over me - could be that I've been married for as long as he can remember. I think the key would be to treat the boy like a person, who will respect you if you show him respect. Normally when we go to the arcade, I ask the kids if they want to go play on their own, or if they want to stay with me and play. I usually play basketball with my oldest son, and I play the video games by myself or with one of the kids. I think if you give him that choice of going on his own or staying with the two of you, he will feel that you're not treating him like a child. Of course, his mother may have a say as to how things will go. But in any case, I would still suggest treating the young man with respect.

Treat him as an adult.

First of all, how did the date go? Was he responsive to you? What kind of vibs did you get? What type of person is he, laid back, uptight?

Yes, boys are extremely territorial of their mothers, (I have 3 boys).

What I've seen my husband do with my sons is (and he is being sincere) try to relate to them using music. Asking them have they heard any new stuff they like and listening to their current favorite song, then he plays them a song he likes (old or new).
Plus, bonus, you can tell a lot about someones state of mind by the music they like or listen to, but you knew that.

The date didn't go. Something came up on her side. I was disappointed, but there has to be two sides for any kind of relationship to develop.

I have received some good input on my question. It appears my information was correct. Teen boys don't like their mothers to get into any kind of relationship. It grosses them out to think of it. And it seems the best way to overcome this is to simply become genuinely interested in the teen's life and interests. It may take more time for some than others.

You won't have any problem being genuine. He will be a very fortunate young man to have you in his life, as will his mother.

The first thing that came to my mind is why are you meeting the son on the first date. I thought it was frowned upon for single parents to introdue their children to people they are dating before they know it is getting serious? Maybe things are different because he is older.

I agree, that isn't the way I'd do it normally. However, I met them together and it seemed logical. Otherwise it might seem like he was being excluded and I was being predatory.

I'm not really looking for dating. She is someone that I would be friends with. I can't really read more into it.

Get to know mom first.