Oh Holly, awwww what an awful gut wrenching situation you find yourself in. I just wish there was a magic wand you could point at your husband and everything would go back to how it was two years ago... awwww but sadly it doesn't exist. That said, if you cast your mind back a couple of years back, please ask yourself these two questions; was I really putting everything I could into this marriage or was I little bit too comfortable and taking it for granted? If the honest answer is yes I was and no I didn't, then clearly he doesn't have the capacity to love you in the way that you want or deserve. I would say close that chapter in your life, move on and throw yourself wholeheartedly into that other love in your life, God. You see if that is the case then he treats his beloved wife like a smartphone, soon as an upgrade is available, he wants to swap. His new girlfriend will find that out for herself but I doubt it will take 18 years. You deserve so much better than that, and I would say close that chapter in your life, move on and throw yourself wholeheartedly into that other love in your life, God. That's not to say you'll never marry again, Jesus in His sermon on the mount, which is very strict teaching, did permit divorcees to remarry if the break up was caused by adultery. But I say to you that whoever divorces his wife for any reason except sexual immorality causes her to commit adultery; and whoever marries a woman who is divorced commits adultery. Matthew 5:32 NKJV. Might I suggest that the new focus in your life is God rather than finding the next one, keep praying and talking to God, and maybe you'll find that God who loves you literally to death, will have you meet a really special guy who will love you faithfully.
However if on reflection your honest answers to my questions above are maybe not and well I suppose, then it's possible that you've been caught asleep on guard duty; well it happens, we're only human. Believe me I'm not trying in any way to justify what your husband has done to you, which is totally unjustifiable. Adultery is evil and wrong, Old Testament and New. If you feel that maybe in reality things weren't as rosy for you both as you thought, then I think it's worth one more try to win your husband back. You know your husband but maybe invite him out to chat things over, somewhere neutral, a restaurant or a bar and ask him to reconsider, telling him how the two of you could be so much better than before. What I would advise is that he has to choose, you're not going to share him, you're not part of his harem. If he's OK with that let him know that you responded to his rejection of you by looking elsewhere for love, but that's forgotten history now. Then the two of you need to plan the next phase of your marriage.
If however he chooses his girlfriend then as painful as it may be, I would say close that chapter in your life, move on and throw yourself wholeheartedly into that other love in your life, God.
I really do hope and pray that you two do get back together. If you, and to anyone else reading this who's married, please make sure you don't slip into a rut, taking your spouse for granted. There's an old saying that if you don't look after your beloved, maybe someone else will. Paul gives us some great advice in setting out a really solid basis of a marriage in Ephesians 5:22-33, it's not politically correct but it's really sound advice if you take up the whole passage rather than cherry picking the bits you like; in summary you need to love each other with depth and each of you has a pivotal role in the marriage. More in 1 Corinthians 7:5, I'd go further and say, don't just not deny each other but actively initiate and tantalise your lover, find out what they like and make them sizzle! There's lots of suggestions and info on YouTube.
You haven't said whether you're husband is a believer or not. If he's not then of course pray for him and openly share your faith- be that light. If he is, so much the better. Ideally a marriage should be a three way thing with God being the fulcrum, pray and worship Him together, share and discuss any blessings that you've received in your Bible study.
A Christian marriage is a fantastic thing for all three of you.
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Dear Lord God, we worship and thank you that your love for us isn't dependent upon our love for you. We can depend upon you because you love us with a perfect love that's just so amazing. Oh if only we can love each other with that love that your son Jesus commanded us to, but Lord with your Holy Spirit within us we can go some way towards that. For each of us that are married, we pray for that special love we need and thrive upon.
For our poor sister Holly we pray for a really special blessing of your wisdom, guide her Lord as she tries to recover her marriage. But overall Lord God, let your will reign supreme in her life, ensuring the best outcome for her and for you. I pray for her that if recovery isn't to be that you'll draw extra close to her, open her eyes to see you dear God, focus upon you as the one true source of unsullied pure love.
We love you dear God.
Amen