You are engaged. This is
totally the time to face these things about yourself and him, to see if you are compatible for long-term marriage commitments together. Better an engagement period that concludes, "We ourselves examined closely, and decided this is not it after all. We'd be better as friends," than entering into a marriage based on lies, and/or cheating.
You could expect better behavior from yourself. You could expect yourself to talk to your fiance seriously about your possible married future when you are engaged.
- Maybe you do not want the same things after all.
- Maybe you come to find you are not yet ready to make a marriage commitment.
- Maybe he has issues of his own.
Give yourselves the time and space to discern and
engage in serious conversation! That is what the engagement period is
for.
Engagement time is not just about examining your desire for open marriage vs (maybe) his desire for closed marriage. But about examining your conflict resolution skills with each other, your readiness, your future plans, etc. Take it seriously.
If your families are not giving you the guidance you need through the engagement, and you don't know how to guide yourselves, consider a pre-marriage class at your county extension office, online, or place of worship.
Conflict-resolution skills come into play your whole adult life, and certainly in a healthy marriage. Having a conflict is not good/bad. It's just life. Conflict happens.
It is
how you weather conflict together. That's the litmus test for how things will be in the long-term marriage commitment. Largely harmonious or largely tumultuous? Avoiding and resentment building? Or deal with it as it comes?
Do not withhold information from your fiance. Do not block clear communication with him. Choose to engage properly. Take the bull by the horns.
- He can own and manage his own feelings. You get the chance to watch him and see if that's what you want to live with in a marriage.
- You can own and manage your feelings. He gets the chance to watch you and see if that's what he wants to live with in a marriage.
I am a fan of long engagements of at least a year. See your intended through a full cycle of seasons, at least. Longer, like two years, is even better How else will you find out he turns into a werewolf every Thanksgiving?
(I joke to keep it light. I'm not minimizing your feelings here.)
Engagement is serious business. Be serious about your own engagement.
Conflict is an opportunity for growth, if you let it. As a couple weathering it out, it builds trust and confidence in each other. For the individuals, it builds confidence and trust in your "I can handle it" bucket.
Embrace rather than deny opportunity here.
What is your fear?
That by talking about it during your engagement time you will learn things?

That if you learn yucky things about him, you will be able to escape a marriage to a wrong-fit partner who is an insecure/jealous man who can't handle his emotions appropriately toward you?
If you cannot handle one conflict with one partner, how will you handle it with many partners?
You can learn do this and can learn to get confident in your own communication skills.
Just spit it out. Don't worry too much about the HOW. Just DO.
Or if you need help with the packaging...
Maybe something like
"I'd like a moment of your time so we could talk about our various wants, needs, and limits for a long term marriage. I'm not sure we want the same things in all areas and I would like to talk for an hour or two to air out my worries. When would be a good time for you? Good times for me are...."
Then when you get to the appointment...
"Look, I feel scared to bring this up. But we are in serious Engagement Time here. So this is the time to bring it up before entering into Marriage. Please listen to my fear and understand that this is hard for me to speak. It may be hard for you to listen. But I want to feel safe in my marriage with my partner. I want to be able to share everything with my marriage partner, not just the sunny side up bits. I want to built trust with my marriage partner.
What are your wants, needs, and limits from marriage? Are you expecting a Closed Marriage? I'm not even sure I want that model. Please tell me what you expect and what model you want for your marriage.
We need to see if marriage is something we can compatibly share together and have both of us do well in it. I'm Engaged to you -- to find out if you are indeed that Marriage Partner I seek. Talk to me please."
GL!
Galagirl