Relationship Troubleshooting

Maybe you've got a messy past when it comes to relationships.
Live rightly now, no matter what happened then.
If you've sinned sexually, it's not all lost. If God could forgive the murderer Paul, the prostitute Rahab and the woman who washed Christ's feet w/ her hair, don't sell short His grace in your life. When God convicts us of sin and we confess it to Him and turn from it, He cleanses us (I Jn 1:9). He helps us begin again. Mercies anew. But yes, there are still consequences, among them pain, guilt, regrets. God can and will help w/ these as well. He is faithful.
Maybe someone has sinned against you. If you've been abused, know that you are still God's precious, beautiful child, that you're still whole and desireable and can have a wonderful God-pleasing marriage.
If a relationship you'd hoped would be lifelong didn't end in marriage, thank God for planning something better for you and strive to recognize that that other relationship wasn't God's best for you.
If your marriage fell apart and you've married again, the marriage you're in now is God's will for you now. Live rightly in it.
If your spouse has been unfaithful or is an unbeliever, you can by the work of the Holy Spirit w/i you love rightly and be a Hosea, be an Abigail. Maybe God will bring your unsaved spouse to Him. He will show you a path of hope.
If there's abuse, get out, get help, pray hard. God could restore even that abuser, but you're not helping by providing opportunity for the abuser to continue in such sin.
Lastly, if it just doesn't seem to be working, if you're afraid you'll alway be alone or you wish you could because you're so unhappy w/ your spouse, know God is still there, He's promised to never leave you or forsake you. Lean on Him. Trust in Him, delight in Him, and He will direct you. He says so in Prov 3:5-6. Strive to love rightly through His strength in the relationships He's given you and know that only He can fill you up. Wait on Him. Either He's trustworthy or He isn't. I believe He is, because He says so. When I take my eyes off Him and fall on my face (often), I ask Him to help me get back up. You can do the same, my friend.