(This started out as a comment, and grew.)
Okay, so first of all, this is not a tradcon space. Their answer to "I slept with a lot of men" is "begone harlot!", which isn't very useful, because "you shouldn't have done that" isn't advice, it's just moralizing.
Okay, the bad news is that because of what you did, you absolutely are less desirable as a wife. Take a deep breath, look in the mirror, and accept that, because getting mad or sad about it does no good. You are not a jar of peanut butter, you can't get unscrewed.
Also useless is blaming men for caring about such things. Men weren't put on this earth to serve you. They get to like what they like and they don't have to answer to you for whether it's "justified" or not.
The important place to start with is to understand why men care about your sexual past.
This may be difficult because men themselves usually do not know why they care about your sexual past. They don't understand their own feelings in this area, and so they cannot explain them. They only know that it "bothers them". So they make up excuses like the ridiculous "stretched out" myth, as if girl parts could somehow wear out, and did so faster with more partners. Or they say that women who have lots of partners can't pair bond, when it's actually the reverse (women who can't pair bond have lots of partners).
They're not trying to lie to you. They just don't know why they are turned off by the idea of committing to a woman who's been with lots of other men... and they are trying to explain it themselves.
But it can be understood. The key word here is "committing". If you look at porn targeted towards men (not the written-word stuff targeted at women), then you notice that the women in it are just about as slutty as it's possible to be, and it doesn't turn the male audience off at all (otherwise they wouldn't be depicted that way).
Men don't care about the sexual past of their casual sex partners, but they care deeply about the sexual past of their romantic partners. This is because they know, even if they can't articulate it, that a woman is at her most sexually available and adventurous with the man she loves the most.
What actually bothers men is the idea of being with someone, of committing to someone, for whom he wasn't the top choice. A man can be patient with a girl who is a virgin... so what if she made him wait for a week, or a month, or whatever? After all, she made everyone else wait for eternity. She's still being at her most sexually available with him in particular.
But once a girl has, for example, a one-night stand, then that indicates something about what it takes to inspire her sexual enthusiasm, and if she she tries to put the brakes on with future partners, this tells them exactly where they stand in the scheme of things. This is why men find the news that his wife had a previous one night stand to be humiliating... she desired that other man more than she desired him.
And it's no good to say "I made a mistake" or "I changed my standards" because all that means is "other men were able to tempt me to do unwise things, but I have more self-control with you".
So, that's the problem with sleeping with a man you just met... because forever afterwards, that's the standard. That's the benchmark. Anything more reserved than that means "I'm just not that into you". And you will never persuade a man otherwise by talking at him.
So, with all this being understood, what can you do?
There are three approaches:
Lie. This may seem immoral, but we don't do moralizing here. Lies can, theoretically, fix the problem. But there are some drawbacks. You can't ever be totally open and honest in your relationship... you have to live that lie for as long as your relationship lasts. Also, if you ever get caught, a lie compounds the injury, and you should not expect the relationship to survive.
Continue to take sexual risks, but with a purpose. This involves being as sexually available to the men you're dating now as you ever were in the past, although now you are at least looking for a relationship. Obviously, this tend to expand your sexual history even further, but at least if you manage to get something going, you didn't withhold from him more than you did with others.
Radical self-improvement. Increase your value on the sexual marketplace so much that you are not the same sexual partner at all, and it's obvious that you can command more effort and investment. This is not as simple as just learning to play the piano, or being slightly nicer to men. It has to be a profound and immediately obvious improvement to the point where a man would not he made ashamed. Think on the order of quitting your drug habit, losing fifty pounds, maybe getting a nose job, and basically reinventing yourself. If you could be in a room with a former sexual partner and your husband, and the FIRST guy feels like a loser, because he had a much worse version of you, that's the magnitude we are talking about.
What do all of these solutions have in common? Well, they all hurt. They all have drawbacks.
But this is the real world, and it wasn't put here to be fulfill your fantasies. This is simply damage control.
It may be tempting to think that you can re-invent yourself as a virgin and simply raise your standards. We've seen plenty of women try to do this, and some of them even find partners. But what they do not find is enthusiastic partners who had other choices. Men who wife up an slut are men who don't have options, and there will reasons why they don't have those options.
So if you want the best partner that is available to you, you're going to have to have a concrete strategy for dealing with what you did, and how that affects their feelings, instead of just complaints about the consequences of your actions. That means more risk, and more compromises... but we can always play the cards we have to the best of our abilities.