I feel like seeing other women outside of my relationship

I (26M) have been in almost a 5 years relationship with (26F), we got engaged a little bit more than a year ago and we’re planning to have our wedding next year, for the context we’ll be calling her “J”.

I wouldn’t like to paint her as a bad person because she’s not so I’ll list her pros and cons.

J is pure hearted, smart, very loving and attached me, she loves me A LOT, has ambitions, family oriented, outgoing and wants to spend time with me every possible second, she has a big heart also.

J is also very possessive, meaning that I have absolutely not one single female friend from my past because she didn’t like any of them, she has very low self esteem when it comes to the relationship and I understand that this could be due to the fact that she got cheated on in her last relationship and she realized this after they broke up (I am her 2nd relationship).

She is a cry baby, she cries at every single argument and if the argument goes sideways then she might get a panic attack and that’s when I always drop everything and snuggle her to calm her down.

She gives a little girl energy, everything for her is roses and rainbows it feels like she’s in a fairytale.

Prior to this relationship, I have hooked up with one woman multiple times and before that I was in a 10 months relationship that ended due to the fact that my gf back then was constantly lying and cheating on me.

For the past year I have been getting these urges to see another women for the sake of getting to know how other women are like or maybe even for sex (I have never acted on my urges and I don’t want to do such a thing to J).

I get these urges every month or 2 weeks and then I distract myself and they’re just gone for some time until I see someone attractive, I thought a lot about it I have considered some points that I’d like to share with you and I’d really appreciate your opinion on the matter as this is something I can’t discuss with J, knowing her if I tell her that I’m getting very attracted to other women then this might break her + she has a very low self-esteem when it comes to this relationship.

1. The little girl energy is always there and I would really appreciate a young women energy also sometimes.

2. The sex is amazing (once a week or two weeks which is not that much) but it feels like I’m having it with a teenager, there is no sexiness in it and it has to always start in the same exact way, kisses in bed.

3. The fact that the only women I am talking to is the women in my family/hers or her friends is a bit bothering me, if I have a work relationship with a female colleague then it is a no for her, meaning if I have time at work I can’t even drink a coffee with a female colleague to kill time.

4. I feel like I’m missing out, is it because I’ve only touched 3 women in my life? I really don’t know it could also be because I don’t know how other women are like and it is like a mysterious territory for me, I mean maybe it is not about sex but just having a casual female friend? Does having a casual female friend count as cheating or inappropriate?

I would really like to work on what I already have as I see J as a wife material and I do trust her but at the same time I can’t really discuss any of this with her because I’ll definitely get the “I’m not good enough for you, I’m a shit person, you don’t love me anymore, you don’t want me anymore” due to her self-esteem.

Is what I’m feeling something common? am I just a shitty person? I am here asking for your advice/guidance.

TL;DR: I have been getting these urges to see other women outside of my relationship and I am not sure why but I have never acted on these urges and I am not planning on doing that.