If you neglect your relationship, it WILL fall apart. Our relationship with God is without a doubt a special one, but don't shrug it off as if you don't need to work on that relationship. The very thought of a baptism and walk away comes to mind immediately especially when becoming a Christian DOES NOT take much education.
I agree, that in any relationship, the work you do reflects on how healthy the relationship is. But that's just talking about the "health" of the relationship. Not the security of the relationship.
I have NO DOUBT in my mind that much like marriage with a spouse that we can and often do break our promises. On purpose? We don't try to. But sometimes we do! We sometimes do it on accident and those are easier to deal with. But its those ones that we do on purpose and we do not RECONCILE with our love that puts the relationship in jeopardy. The question is, can you break your promise with God and not reconcile with him? Absolutely! Where would that put you when the end comes? I wouldn't bet the farm that I'm "sealed" in with God.
We absolutely break our promises. We are imperfect sinners. God is not. His promises will always be true. He cannot lie.
Ephesians 1:13-14
In Him, you also, after listening to the message of truth, the gospel of your salvation—having also believed, you were sealed in Him with the Holy Spirit of promise, who is given as a pledge of our inheritance, with a view to the redemption of God’s own possession, to the praise of His glory.
This is not fair and it would not be just of God to accept someone into heaven who freely walked away from him for the worldly desire instead after you break your promise to him.
Fair, says who? God has sealed the true believer with the Holy Spirit. This "seal" is a guarantee from God. It's a guarantee, from God, because of who He is, and not because of who we are. God's promises are not contingent on us. If they were, He would be a pretty weak God, wouldn't He?