Me [29 M] with my girlfriend [44 F] 3 months, affection has died down a lot

Let me set the scene first of all. My wife and I are both 29 (married 4 years), and have worked really hard to have a quite boring life in the suburbs. It's really nice, and also a little boring at times. With that in mind, we opened our relationship and it has been great for both of us.

I met Jamie (44) at a hockey event, and we became friends and started hooking up. (She is married as well, everyone is on board, she has met my wife and I've met her husband).

After about a month of FWB type of situation, she asked about being my girlfriend. I thought about it, cleared it with my wife, and agreed.

The first 2 months, she was extremely affectionate, texting all the time, sending me cute pictures, telling me how much she missed me, (I can't believe I won't see you for a whole week, ect). I was really soaking up all the attention and just loving it, especially after years of just work work working and no social life.

The past 3-4 weeks though, it has died down significantly. We still text every day, just not nearly as much. No I miss you's, or can't wait to see you's, things like that. She used to text me the second she woke up, now it'll be later in the afternoon, stuff like that. We still meet up, she still responds to messages and all.

I think what has happened it that I got used to the constant attention and affection, and now that the "honeymoon phase" is over and it's naturally settling down into a more manageable and sustainable level of attention, I'm feeling like she doesn't like me as much.

I think there are 2 issues: First of all, I got used to the initial level of attention and kind of set that as the standard, and as it's naturally settled down, it's making me insecure even though I don't really think I have a reason to be. Second, I have no friends of social life besides her. Maybe making some other friends and talking to other girls will help take her off my mind a little?

tl;dr: Honeymoon phase is over. How do I deal with the natural downswing in attention and affection?