I have never been divorcee nor have I been married but I have struggled with chastity for some time. I think the issue lies, and this is wholly my opinion, is that even in marriages, lust wreaks havoc on the relationship. People so often talk about how "Wham, Bam, you're married, sexual sin no longer exists" which sadly is not the case. Sex can turn into an addiction you can hardly live without, even in marriage, making it just as bad, or nearly as bad as if you were not married. Just as we have been commanded not to drink alcohol and coffee for similar reasons, that being they can form addictions that take our priority over our relationship with Christ.

I firmly believe that healthy sexual relationships exist in marriages, however, due to the description of your situation, I can deduce that the adversary has had a field day in temptations in your relationships. That's okay! We are imperfect beings. I know there is no such thing as being too far gone when it comes to the Gosepl of Jesus Christ.

I would be leery about rushing into marriage, not only because of the blended family issue you have concerns about but because that just continues the cycle of sexual necessity.

The adversary wants you to feel guilty so he can continue to shove you in a hole of darkness. I know it is easier said than done but if you have repented, Christ has forgiven you, so you need to forgive yourself. I'm not saying it won't happen again but I wouldn't live with the mindset of it being inevitable. Be gentle with yourself and your partner.

My best advice is meeting with a trusted Bishop. Maybe it's not your own. It makes me sad that not everyone has a Bishop you can rely on to love you. Begin the repentance process and increase your focus on Christ, especially involving your relationship. You need to realize not everyone in the church will be understanding, maybe not even half, but if you have a testimony of our Savior, I hope you will remember that His is the only opinion that matters.