Long time (15+ years) open relationship person here. Very stable, kids with my partners, family, live together, still swing and play outside my relationships, the works. Poly + nonmonogamy. Just as a reference for where I come from.

Your wife has NRE. It's normal. It's also terribly difficult. I am at a point now where it wears off in a week or so; after over a decade. In the beginning it was something that lasted for months.

Here's my few bullet points to make this successful for you:

1) you are not ready for an open relationship. You don't open up to save a marriage, just like you don't have a baby. You need to be solid first. Opening up is like taking a flashlight to the dirt under your bed and finding the ickies. Clean them out together first.

2) you need to do more reading and talking as a couple and you need to get involved with your community so you can see examples of this working well. I recommend ethical slut, more than two, and sex at dawn for beginning reading material.

3) if the swingers club didn't appeal to your demographic, getting involved in your community can help. The younger folks tend to congregate together. There are lots of house parties and events for your bags bracket, whatever it may be. I am in my thirties and pretty fit and get invited to parties where the crowd is similar. People like playing with their peers. Join your community and get invited. Swinging together is so much less stressful for new couples.

4) don't compare yourself to her other relationships. That's crappy. They're doing something different because they are a different person. They are not a sex toy for your marriage. Stop dehumanizing them and accept that your wife will do things differently with others than with you because they are a real person with their own needs and wants and dynamic with your wife.

5)while I'm not an advocate for lots of rules personally (my group has none, just protection/safe sex boundaries) you really need to make sure your time is fairly divided. This is especially important with a child in the mix. Get equal time out, and also be blocking off time for your marriage and solo time.

You can do this, but you need to do more prep work and stop treating other partners bas an extension of your marriage or a sex toy, and get your relationship in order first.